Method of processing traffic information and digital broadcast system

ABSTRACT

A digital broadcast transmitting/receiving system and a method for processing data are disclosed. The method for processing data may enhance the receiving performance of the receiving system by performing additional coding and multiplexing processes on the traffic information data and transmitting the processed data. Thus, robustness is provided to the traffic information data, thereby enabling the data to respond strongly against the channel environment which is always under constant and vast change.

This application is a Continuation of U.S. patent application Ser. No.11/541,561 filed Oct. 3, 2006 now U.S. Pat. No. 7,804,860 which claimsthe benefit of Korean Patent Application Nos. 10-2005-0093639 filed Oct.5, 2005; 10-2006-0039117 filed Apr. 29, 2006; 10-2006-0089736 filed Sep.15, 2006 and 10-2006-0023214 filed Mar. 13, 2006, all of which arehereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a digital broadcast system, and moreparticularly, to a digital broadcast transmitting/receiving system and amethod for processing data.

2. Discussion of the Related Art

Presently, the technology for processing digital signals is beingdeveloped at a vast rate, and, as a larger number of the population usesthe Internet, digital electric appliances, computers, and the Internetare being integrated. Therefore, in order to meet with the variousrequirements of the users, a system that can add video/audio datathrough a digital broadcasting (or television) channel so as to transmitdiverse supplemental information needs to be developed.

Some users may assume that supplemental data broadcasting would beapplied by using a PC card or a portable device having a simple in-doorantenna attached thereto. However, when used indoors, the intensity ofthe signals may decrease due to a blockage caused by the walls ordisturbance caused by approaching or proximate mobile objects.Accordingly, the performance of the received digital signals may bedeteriorated due to a ghost effect and noise caused by reflected waves.Therefore, a system highly resistant to (or robust against) ghosteffects and noise is required to be developed. Particularly, in orderfor the supplemental data to be used in portable and mobile broadcastreceivers, a higher degree of resistance (or robustness) against channelinterruption and noise is required.

The supplemental data are generally transmitted by a time-divisionmethod through the same channel as the MPEG video/audio data. However,with the advent of digital broadcasting, ATSC VSB digital televisionreceivers that receive only MPEG video/audio data are already suppliedto the market. Therefore, the supplemental data that are transmittedthrough the same channel as the MPEG video/audio data should notinfluence the conventional. ATSC VSB receivers that are provided in themarket. In other words, this may be defined as ATSC VSB compatibility,and the supplemental data broadcast system should be compatible with theATSC VSB system. Herein, the supplemental data may also be referred toas enhanced data or EVSB data. Furthermore, as the number of possessedautomobiles (or cars) is in constant increase, and with the influence ofthe working-5-days-a-week policy (which eventually leads to an increasein the usage of cars), the need for traffic information is alsoincreasing accordingly.

SUMMARY OF THE INVENTION

Accordingly, the present invention is directed to a digital broadcasttransmitting/receiving system and a method for processing data thatsubstantially obviate one or more problems due to limitations anddisadvantages of the related art.

An object of the present invention is to provide a digital broadcastsystem and a method for processing data that can be compatible to theATSC VSB system, that is suitable for transmitting enhanced data, andthat is resistant to and robust against noise.

Another object of the present invention is to provide a digitalbroadcast transmitting/receiving system and a method for processing datathat can effectively receive and transmit traffic information byapplying the traffic information data as the enhanced data.

Another object of the present invention is to provide a digitalbroadcast transmitting/receiving system and a method for processing datathat can enhance the receiving performance of the receiving system byperforming additional coding on the traffic information data andtransmitting the processed data.

A further object of the present invention is to provide a digitalbroadcast transmitting/receiving system and a method for processing datathat can enhance the receiving performance of the receiving system bymultiplexing the known data, which correspond to data known in advanceaccording to an agreement between the transmitting system and thereceiving system, and the traffic information data.

Additional advantages, objects, and features of the invention will beset forth in part in the description which follows and in part willbecome apparent to those having ordinary skill in the art uponexamination of the following or may be learned from practice of theinvention. The objectives and other advantages of the invention may berealized and attained by the structure particularly pointed out in thewritten description and claims hereof as well as the appended drawings.

To achieve these objects and other advantages and in accordance with thepurpose of the invention, as embodied and broadly described herein, adigital broadcast transmitter according to an embodiment of the presentinvention includes a traffic information message generator, apre-processor, a multiplexer, a trellis encoder, and a transmitter.

The traffic information message generator may generate a trafficinformation message including status information, which includes atleast one of prediction information on a link travel time and predictioninformation on link average speed, and location informationcorresponding to the prediction information. The pre-processor maypre-process traffic information data including the traffic informationmessage by encoding the traffic information data and by generating atraffic information data packet including the encoded trafficinformation data and known data. The multiplexer may multiplex thetraffic information data packet with one or more main audio and video(AV) data packets. The trellis encoder may have at least one memory andtrellis-encoding the multiplexed data packets, the at least one memorybeing initialized by initialization data when data outputted from themultiplexer correspond to a beginning of a known data sequence. The datatransmission unit may insert synchronization data into thetrellis-encoded data, modulating the trellis-encoded data having thesynchronization data, and transmitting the modulated data.

In other aspect of the present invention, a digital broadcasttransmitter may include a traffic information message generator, apre-processor, a multiplexer, a post-processor, a data encoding andinterleaving unit, a trellis encoder, and a transmitter.

The traffic information message generator may generate a trafficinformation message including status information, which includes atleast one of prediction information on a link travel time and predictioninformation on link average speed, and location informationcorresponding to the prediction information. The pre-processor maypro-process traffic information data including the traffic informationmessage by encoding the traffic information data for at least one oferror correction and error detection and by generating a trafficinformation data packet including the encoded traffic information dataand known data. The multiplexer may multiplex the traffic informationdata packet with one or more main audio and video (AV) data packets. Thepost-processor post-processing the multiplexed data by encoding onlytraffic information data included in the multiplexed data with a codingrate of G/H, wherein G and H are positive integers and G is less than H.The data encoding and interleaving unit may add first parity data intothe post-processed data and interleave the post-processed data havingthe first parity data. The trellis encoder may have at least one memoryand trellis-encoding the interleaved data, the at least one memory beinginitialized by initialization data when data outputted from the dataencoding and interleaving unit correspond to a beginning of a known datasequence. The data transmission unit may insert synchronization datainto the trellis-encoded data, modulating the trellis-encoded datahaving the synchronization data, and transmitting the modulated data.

In another aspect of the present invention, a digital broadcasttransmitter may include a traffic information message generator, apre-processor, a multiplexer, a data encoding and interleaving unit, apost-processor, a trellis encoder, and a transmitter.

The traffic information message generator may generate a trafficinformation message including status information, which includes atleast one of prediction information on a link travel time and predictioninformation on link average speed, and location informationcorresponding to the prediction information. The pre-processor maypre-process traffic information data including the traffic informationmessage by encoding the traffic information data for at least one oferror correction and error detection and by generating a trafficinformation data packet including the encoded traffic information dataand known data. The multiplexer may multiplex the traffic informationdata packet with one or more main audio and video (AV) data packets. Thedata encoding and interleaving unit may add first parity data into themultiplexed data and interleave the multiplexed data having the paritydata. The post-processor may post-process the interleaved data by codingonly traffic information data included in the interleaved data with acoding rate of G/H, wherein G and H are positive integers and G is lessthan H. The trellis encoder having at least one memory andtrellis-encoding the post-processed data, the at least one memory beinginitialized by initialization data when data outputted from thepost-processor correspond to a beginning of a known data sequence. Thedata transmission unit may insert synchronization data into thetrellis-encoded data, modulating the trellis-encoded data having thesynchronization data, and the transmitting the modulated data.

In another aspect of the present invention, a method of processingtraffic data in a digital transmitter may include generating a trafficinformation message including status information, which includes atleast one of prediction information on a link travel time and predictioninformation on link average speed, and location informationcorresponding to the prediction information, generating at least onesystem information table required for decoding the traffic informationmessage, and multiplexing the traffic information message and the systeminformation table.

In another aspect of the present invention, a digital broadcasttransmitter may include a traffic information message generator, asystem information generator, and a multiplexer.

The traffic information message generator may generate a trafficinformation message including status information, which includes atleast one of prediction information on a link travel time and predictioninformation on link average speed, and location informationcorresponding to the prediction information. The system informationgenerator may generate system information required for decoding atraffic information message. The multiplexer may multiplex the trafficinformation message and the system information.

In another aspect of the present invention, a data structure may includesystem information required for decoding a traffic information messageincluding status information, which includes at least one of predictioninformation on a link travel time and prediction information on linkaverage speed, and location information corresponding to the predictioninformation, the system information comprising a traffic informationtable which includes at least one of a traffic information applicationidentifier, a service component identifier, and service information.

In another aspect of the present invention, a method of processingtraffic information data in a digital broadcast receiver may includereceiving traffic information data including a traffic informationmessage and system information, demultiplexing the traffic informationmessage and the system information from the traffic information data,and decoding the traffic information message using the systeminformation, thereby extracting status information, which includes atleast one of prediction information on a link travel time and predictioninformation on link average speed, and location informationcorresponding to the prediction information.

In a further aspect of the present invention, a digital broadcastreceiver may include a demodulator, a data demultiplexing and decodingunit, a data storage, and an application manager.

The demodulator may demodulate traffic information data including atraffic information message and system information and performing errorcorrection to the demodulated data. The data demultiplexing and decodingunit may demultiplex the traffic information message and systeminformation from the error-corrected data and decode the demultiplexedtraffic information message using the system information. The datastorage may store the system information and the decoded trafficinformation message. The application manager may provide a trafficinformation service to a user using the stored traffic informationmessage by extracting status information, which includes at least one ofprediction information on a link travel time and prediction informationon link average speed, and location information corresponding to theprediction information.

It is to be understood that both the foregoing general description andthe following detailed description of the present invention areexemplary and explanatory and are intended to provide furtherexplanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this application, illustrate embodiments of the invention andtogether with the description serve to explain the principle of theinvention. In the drawings:

FIG. 1 illustrates a transmission format of traffic informationaccording to the present invention;

FIG. 2 a illustrates a syntax of TPEG-CTT messages;

FIG. 2 b shows syntax of formats of components carrying congestionstatus information;

FIGS. 2 c and 2 d show syntax of a CTT component carrying CTT events andlocation information, respectively;

FIG. 2 e shows syntax of a CTT component carrying additional informationof congestion status information;

FIG. 3 a illustrates a syntax of the traffic/congestion informationincluded in the CTT status container;

FIGS. 3 b through 3 e illustrate syntaxes of the average link speed, thelink travel time, the link delay, and the congestion type included inthe status component shown in FIG. 3 a, respectively;

FIG. 4 a illustrates a syntax of the traffic/congestion predictioninformation included in the CTT status container;

FIGS. 4 b through 4 d illustrate syntaxes of the predicted average linkspeed, the predicted link travel time, and the tendency informationincluded in the status component shown in FIG. 4 a, respectively;

FIG. 5 a illustrates an example of a database storing the history oftraffic status at each link for providing the traffic/congestionprediction information;

FIG. 5 b illustrates an example of a graphical user interface configuredto predict the average speed at a specific link using the database shownin FIG. 5 a;

FIG. 6 illustrates a block view showing a general structure of a digitalbroadcast transmitting system according to an embodiment of the present;

FIG. 7 illustrates a syntax structure of traffic information descriptorsaccording to an embodiment of the present invention;

FIG. 8 illustrates an example of table that may include the trafficinformation descriptors of FIG. 7;

FIG. 9 illustrates a syntax structure of a virtual channel table whereinthe traffic information descriptors of FIG. 7 are included according toan embodiment of the present invention;

FIG. 10 illustrates a block view showing a structure of a digitalbroadcast transmitting system according to a first embodiment of thepresent invention;

FIG. 11 illustrates an example of a detailed block view showing an E-VSBpre-processor of FIG. 10;

FIG. 12A and FIG. 12B each illustrates a data structure before and aftera data deinterleaver of FIG. 10, respectively;

FIG. 13 illustrates a block view showing a structure of a digitalbroadcast transmitting system according to a second embodiment of thepresent invention;

FIG. 14 illustrates an example of a detailed block view showing an E-VSBpre-processor of FIG. 13;

FIG. 15 illustrates an example of a detailed block view showing an E-VSBpost-processor of FIG. 13;

FIG. 16 illustrates a block view showing a structure of a digitalbroadcast transmitting system according to a third embodiment of thepresent invention;

FIG. 17 illustrates a block view of a digital broadcast receiving systemaccording to an embodiment of the present invention;

FIG. 18 illustrates process steps of receiving traffic information dataaccording to an embodiment of the present invention;

FIG. 19 illustrates a detailed view of a demodulator of FIG. 17according to a first embodiment of the present invention; and

FIG. 20 illustrates a detailed view of a demodulator of FIG. 17according to a second embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to the preferred embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings. Wherever possible, the same reference numbers will be usedthroughout the drawings to refer to the same or like parts. In addition,although the terms used in the present invention are selected fromgenerally known and used terms, some of the terms mentioned in thedescription of the present invention have been selected by the applicantat his or her discretion, the detailed meanings of which are describedin relevant parts of the description herein. Furthermore, it is requiredthat the present invention is understood, not simply by the actual termsused but by the meaning of each term lying within.

In the present invention, the known data refer to a set of data known inadvance according to an agreement between a transmitting system and areceiving system. The main data refer to a set of data that can bereceived by a conventional receiving system. Both known data and maindata may include video data and/or audio data. Also, in the presentinvention, the enhanced data may refer to data including information,such as a program execution file, stock information, trafficinformation, and so on. The enhanced data may also include video dataand/or audio data. Such enhanced data may include traffic information,data for providing data service, system information for ground (orterrestrial) wave broadcasting such as PSI and/or PSIP, systeminformation for cable broadcasting such as out of band systeminformation (OOB-SI), supplemental data configured of diverse Javalanguage or HTML language for data services providing a wide range ofapplications, audio data, and video data. The enhanced data may alsoinclude various control software for controlling the receiver, and metadata that are configured of an XML language, for example, in order toprovide diverse information to the user.

In the description of the present invention, traffic information datawill be applied for the enhanced data, so as to be transmitted andreceived. A road searching service and a traffic information providingservice according to the present invention may be applied to a varietyof digital broadcast standards. Representative examples of the digitalbroadcast standards are a European Digital Audio Broadcasting (DAB)service based on the Eureka-147 [ETSI EN 300 401], a Digital VideoBroadcasting-Terrestrial (DVB-T) service provided in Europe, a DigitalVideo Broadcasting-Handheld (DVB-H) service also provided in Europe, aMedia Forward Link Only (FLO) service provided in the United States, anda Digital Multimedia Broadcasting (DMB) service that is provided in theRepublic of Korea. The DMB service of the Republic of Korea isclassified into a Terrestrial Digital Multimedia Broadcasting (T-DMB)service based on the Eureka-147 and a Satellite Digital MultimediaBroadcasting (S-DMB) service using satellite communication.

Herein, the traffic information includes information on publictransportation, congestion and travel time, road traffic, emergencyevents and situation, and so on. The traffic information also includesinformation associated with all types of transportation means includingtrain, ship (or cruiser), airplane, and so on. Furthermore, the trafficinformation may also include information on factors that may influencetraffic, such as travel information, information parking facilities,weather information, environmental pollution information, and so on.Most particularly, although the congestion and travel time (hereinafterreferred to as “CTT”) information is given as an example of the presentinvention, any other information type may be applied herein.Furthermore, as long as the term indicates a particular function, theterms used in the present invention are not limited only to the onesused in the description set forth herein.

The term “traffic status” is indicative of a road congestion status(i.e., a flow status), however, it is not limited to the above-mentionedroad congestion status and can be applied to similar examples asnecessary. For the convenience of description and better understandingof the present invention, the term “traffic status” is referred to as aCongestion and Travel. Time Information (CTT) status. Theabove-mentioned CTT status includes CTT status information, and CTTstatus prediction information, additional information, and so on. Theterm “section” or “link” is indicative of a specific area of roads.However, it is not limited to the above-mentioned meanings and may beapplied to other similar meanings as necessary.

The traffic information service according to the present invention isprovided to the users by a receiver having only one or none of anelectronic map and a GPS mounted therein in the form of at least one ofa text, a voice, a graphic, a still image, and a motion picture. Thetraffic information data are configured and transmitted by trafficinformation message units. More specifically, the traffic informationmessage is the smallest unit for transmitting the traffic information.Herein, information on a single traffic information application isincluded in a traffic information message. In the present invention, theterm “Transport Protocol Expert Group (TPEG)” will be used on thetraffic information for simplicity. Furthermore, as described above, aslong as the term indicates a particular function, the terms used in thepresent invention are not limited only to the ones used in thedescription set forth herein.

The traffic information application corresponds to the highest hierarchywithin an ISO/OSI protocol stack. Each traffic information applicationis assigned with a unique identification number, which is referred to asan application identification (AID). Each time a new application isdeveloped and created, a new application identification is assigned. Forexample, each of the congestion and travel time (CTT) information, theroad traffic message (RTM), the public transport information (PTI), andso on, is a traffic information application that is given uniqueapplication identification. The traffic information data correspond to astream form including various traffic information messages. Herein, thetraffic information messages correspond to at least one application.

FIG. 1 illustrates an example of two traffic information applications(e.g., CTT and RTM) being included in a stream. Traffic informationmessage generator (not shown in figure) generating a traffic informationmessage can be a broadcast station. For simplicity of the description ofthe present invention, the traffic information message generator isreferred to as a traffic information providing server. The trafficinformation message generator construct in a traffic information messageunit traffic congestion information collected from various sources(e.g., operator input, or information received from another server orprobe cars through a network).

At this point, each traffic information message has the same containerconfiguration, which may be referred to as a traffic information (orTPEG) message container. The CTT message container described hereincorresponds to one of the traffic information message containers. Morespecifically, the CTT message container according to the presentinvention, which transmits the CTT message, includes a CTT messagemanagement container 102, a CTT-status container 104, and aTPEG-location container 106.

The above-mentioned CTT message management container 102 includes amessage identification information and date and time information, anduses the message identification information and the date and timeinformation as management information of the information received by thereceiving system. The message ID information requisite for the messageincludes a message identifier (MID) and a version number (VER). In thiscase, the message ID (MID) is indicative of an identifier of a singlemessage associated with individual status of a service component. TheMID according to the present invention gradually increases the MIDnumber from 0 by a predetermined number “1” at a time. If the MID valuereaches the maximum value “65535”, the maximum value “65535” isinitialized to zero. The version number (VER) is indicative of asequential number for identifying successive messages having a singlemessage ID. The version number according to the present invention may bedetermined to be any one of 0 to 255, and it should be noted that theversion number is sequentially increased in the range from 0 to 255.

The above-mentioned CTT status container 104 includes a plurality of CTTcomponents (ctt_component), each of which includes CTT statusinformation. The CTT status component (ctt_component) includes CTTstatus information (ID “80 hex”), CTT status prediction information (ID“81 hex”), and additional information (ID “8A hex”), etc. The CTT statuscomponent (ctt_component) to which the identifier. “80 hex” is assignedincludes a status component (status_component). The status component(status_component) includes an average link speed, a travel time, a linkdelay time, and a congestion type.

The TPEG location container 106 includes a plurality of TPEG locationcomponents (tpeg_loc_component) equipped with link location information.In this case, the location information may be information based on acoordinates system and information of a predetermined link ID. Each TPEGlocation container (tpeg_loc_container) includes at least one locationcoordinates component (location_coordinates_component) to which an ID“00 hex” is assigned. The above-mentioned CTT component includesinformation of a link as a target object both the CTT status informationand the CTT status prediction information. The above-mentioned linkinformation includes a road-type list, a WGS 84 indicative of locationcoordinates, a link shape point, a link ID, link description, and so on.

A CTT message, whose syntax is shown in FIG. 2 a, may include a CTTmessage management container 102, a CTT status container 104 (orApplication Event Container), and TPEG location container 106. TheTPEG-CTT message may also include different type of containers otherthan, less than, or in addition to the CTT status container as in theTPEG-CTT message.

In various implementations, a CTT status container and a TPEG locationcontainer, as illustrated in FIG. 2 b, are composed of one or more CTTcomponents 202. Each of CTT components may be constructed according tothe syntax shown in FIG. 2 c if it carries congestion status informationwhile it may be constructed according to the syntax shown in FIG. 2 d ifthe component carries location information.

A CTT status container 104 may be composed of one component or aplurality of CTT components. In various implementations, CTT componentsincluding an ID of 80h (notation ‘h’ means hexadecimal) or 84h includesone or more status components including basic traffic information suchas the average link speed, link travel time, link delay, or congestiontype. In the description, specific IDs are described as assignments tostructures associated with specific information. The actual value of anassigned ID (e.g., 80h) is exemplary, and different implementations mayassign different values for specific associations or circumstances.

In various implementations, CTT components including an ID of 81hinclude one or more status components including predicted CTT status.The predicted CTT status may include predicted average link speed,predicted link travel time, or congestion acceleration tendency. Thecongestion acceleration tendency may include information indicative ofthe tendency of congestion status. The congestion acceleration tendencywill be described as a type of prediction information as the congestionstatus in the near future may be predicted from it.

In various implementations, the TPEG-CTT message may comprise CTTcomponents structured as FIG. 2 e to deliver additional information oftraffic information. As shown, an identifier 8Ah may be assigned to theCTT component carrying additional information, and a language code thatis indicative of language used for the additional information may alsobe included in the CTT component.

FIG. 3 a shows an example of a syntax of the CTT component included inthe CTT status container, which delivers the current congestion andtravel time status. The CTT component may be assigned an ID 212including a value of 80h or 84h and may include m status components 216and a field 214 indicative of the length of the data included in thestatus components included therein, the length being expressed in theunit of byte. Other units, such as bit, may be used.

The status components 216 may include information on the average linkspeed, the link travel time, the link delay, and/or the congestion type.The syntax, according to one implementation, of each of which, is shownin FIGS. 3 b, 3 c, 3 d, and 3 e, respectively. In one implementation,status components delivering the average link speed, the link traveltime, the link delay, and the congestion type are assigned IDs of ‘00’,‘01’, ‘02’, and ‘03’, respectively. The link delay may be, for example,the delay in the time required to pass through the link under currenttraffic condition with respect to the time required to pass through thelink at a limit speed specified in the link. The link delay may beexpressed in the unit of minute, second, tens or tenths of seconds, oranother unit. The link delay may be calculated with respect to theaverage time required to pass the link on the same days or in the sametime slot. The link delay may enable traffic information receivingterminals that do not have information on each link (e.g., speed limitin the link, length of the link, etc) to expect the time required topass a link.

FIG. 4 a shows an example of a syntax of the CTT component included inthe CTT status container, which delivers the predicted congestion andtravel time status. The CTT component may be assigned an ID 222including, a value of 81h and may include m status components 226 and afield 224 indicative of the length of the data included in the statuscomponents included therein, the length, may be, for example, expressedin the unit of byte.

The status components 226 may include information on the predictedaverage link speed, the predicted link travel time, and/or, thecongestion acceleration tendency, the syntax, according to oneimplementation, of each of which, is shown in FIGS. 4 b, 4 c, and 4 d,respectively. The status components delivering the predicted averagelink speed, the predicted link travel time, and the congestionacceleration tendency may be assigned IDs of ‘00’, ‘01’, and ‘02’,respectively.

Alternatively, the predicted congestion and travel time status may bedelivered by the CTT component that delivers the current congestion andtravel time status (e.g., average link speed, link travel time, linkdelay, congestion type) including an ID of 80h or 84h. In this case, thestatus components delivering the predicted congestion and travel timestatus may be assigned IDs different from the IDs of the statuscomponents delivering the current congestion and travel time status.

The traffic information provider (for example, a traffic informationServer) may create predicted status information shown, according to oneimplementation, in FIGS. 4 b through 4 d based on the trafficinformation which may be collected from various sources and/or its owntraffic information database, which will be described in detail below.

To provide predicted traffic information, the traffic informationprovider may store the average speed at each link according to day, timeslot, week, month, or year. For example, in one implementation, thetraffic information provider may store the average speed at each link atintervals, such as every 30 minutes, as shown in FIG. 5 a. The unit ofthe values shown in FIG. 5 a is km/h, though other units, such as m/s,may be used.

Additionally, in one implementation, the traffic information providermay store the average speed, or other information, such as travel timeor congestion, of links for which the traffic information is currentlyprovided at intervals for a predetermined period of time (e.g., 3 hours)and compare the pattern of change in the average speed for the period oftime with the pattern of change in the same time slot of the same daystored in the database. For example, if FIG. 5 b shows the pattern ofchange in the average speed for the past 3 hours from 4:30 pm on aMonday afternoon (A), the traffic information provider compares the datawith the average speeds of from 1:30 pm to 4:30 pm stored in thedatabase (B). If the difference (e.g., the sum of the absolute values ofthe difference in average speeds at each corresponding time or aweighted sum thereof) is less than a predetermined threshold, thetraffic information provider reads the average speed B1 at 30 minutesafter the current time (i.e., the average speed at 5:00 pm) from thedatabase and transmits the value as the predicted average speed in thecorresponding link according to the syntax shown in FIG. 4 b. Thepredicted average link speed may be expressed in the unit of km/h, forexample. The predicted time (e.g., 5:00 pm in the previous example) mayalso be transmitted in the form of the syntax shown in FIG. 4 b, forexample in UTC (Universal Time Coordinated) format.

Explaining FIG. 4 b in more detail, the predicted time in UTC format maybe indicative of a target time or date in the future, and the predictedspeed indicates average speed (in km/h, for example) on a link at thetarget time or date, such as, a day of year, month of year, year,holiday, time of day, rush hour, event, morning/afternoon/evening. Forexample, the link may be an inter-road between cities, a bridge, or aroad between intersections. The data may be incorporated into thecomponent in units of a byte unit, and/or it may be incorporated inunits of a bit or a long byte, according to data size. In addition, thespeed may be expressed in various units, for example, m/sec, mile/hour,etc.

In one implementation, if the calculated difference exceeds thepredetermined threshold, i.e., it is determined that the pattern ofchange in the average speed stored in the database does not match thepattern of change in the measured average speed, the traffic informationprovider may not provide the predicted average link speed, oralternatively, the traffic information provider may estimate thepredicted average link speed A1 from the average link speeds extractedfor the past 3 hours and provide the estimated value as the predictedaverage link speed. Various processes may be used to estimate theaverage speed from the measured average speed values. One process, forexample, involves calculation of a weighted sum which gives the latestsample value the highest weight and gives the oldest sample value thelowest weight. For example, the predicted speed A1 in FIG. 5 b can beextracted by calculating 0.5×current speed+0.2×speed of 30 minutesago+0.1×speed of 1 hour ago+0.1×speed of 1.5 hours ago+0.05×speed of 2hours ago+0.05×2.5 hours ago, etc.

After calculating the predicted average link speed in the aforementionedway, the traffic information provider may calculate the predicted traveltime of each link and transmit the predicted travel time of each linkalong with associated predicted time according to the syntax shown inFIG. 4 c. The predicted travel time may be calculated by multiplying thepredicted average speed at each link by the length of the correspondinglink stored in the database. The predicted travel time may be expressedin the unit of minutes, tens of seconds, second, or a unit smaller thanseconds, for example.

When providing the average speed in a particular link, the trafficinformation provider may compare the current average speed with theaverage speed at the previous time slot and provide the tendency ofchange in the average link speeds 41 according to the syntax shown inFIG. 4 d. In one implementation, the information, which is called thecongestion acceleration tendency, may have one value among severalvalues defined by a table shown in FIG. 4 d. For example, theinformation may be assigned 1 if the current average speed is higherthan the average speed of 30 minutes ago. The congestion accelerationtendency may be assigned 2 if the current average speed is lower thanthe average speed of 30 minutes ago. The congestion accelerationtendency may be assigned 3 if the average speed remains unchanged. Ifthere is no available data to compare, the congestion accelerationtendency may be assigned 0. The congestion acceleration tendencyinformation may enable a driver to choose a route that shows improvementin the traffic congestion from among several possible routes showingsimilar average speeds. Instead of providing the congestion accelerationtendency in the form of a number (e.g., 1, 2, 3, etc.), the trafficinformation provider may provide the rate of change of the averagespeed, i.e., the slope in the graph shown in FIG. 5 b as the congestionacceleration tendency, or other indicia or descriptors.

In one implementation, the traffic information provider may prevent thesize of information which it should transmit from becoming excessivelylarge by maintaining the ratio of the current congestion and travel timestatus to the predicted congestion and travel time status below anappropriate level (e.g., 3:1).

The above described traffic information data require a more stablereceiving performance than the general audio and/or video data, i.e.,the main data. In case of the main data, small errors that cannot benoticed by the eyes and ears of a user are not problematic. Conversely,in case of the traffic information data, even a 1-bit size error cancause a serious problem. Therefore, the traffic information data areprocessed with an additional coding process, which is then multiplexedwith the main data and transmitted. Thus, robustness is provided to thetraffic information data, such as the CTT data, thereby enabling thedata to respond strongly against the channel environment which is alwaysunder constant and vast change. At this point, system information isrequired in order to extract the traffic information data from thechannel through which the traffic information data are transmitted and,then, to decode the extracted traffic information data. In some cases,the system information is referred to as service information. The systeminformation may include channel information, event information, and soon.

In the preferred embodiment of the present invention, program specificinformation/program and system information protocol (PSI/PSIP) isapplied as the system information. However, the present invention is notlimited only to the example given in the description set forth herein.More specifically, if the system information corresponds to a protocolbeing transmitted in a table format may be applied to the presentinvention regardless of name of the system information. The PSI is anMPEG-2 system standard defined for classifying the channels and theprograms. And, PSIP is an advanced television systems committee (ATSC)standard having channels and programs that can be classified.

Herein, the PSI may include a program association table (PAT), aconditional access table (CAT), a program map table (PMT), and a networkinformation table (NIT). More specifically, the PAT corresponds to aspecial information that can be transmitted by a packet having a packetidentification (PID) of ‘0’. The PAT transmits the corresponding PIDinformation of the PMT and the corresponding PID information of the NITfor each program. The CAT transmits information on a paid broadcastsystem that is used by the transmitting end. The PMT transmits PIDinformation of a transport stream packet to which the programidentification number and separate bit sequences, such as video data andaudio data configuring the corresponding program, are transmitted. ThePMT also transmits PID information to which the PCR is transmitted. TheNIT transmits information of the actual transmission network.

On the other hand, the PISP may include a virtual channel table (VCT), asystem time table (STT), a rating region table (RRT), an extended texttable (ETT), a direct channel change table (DCCT), a direct channelchange selection code table (DCCSCT), an event information table (EIT),and a master guide table (MGT). The VCT transmits information on thevirtual channel such as channel information for selecting the channeland a packet identification (PID) for receiving audio data and/or videodata. More specifically, by parsing the VCT, PIDs of the audio data andvideo data corresponding to the broadcast program that is beingtransmitted through the channel along with the channel name, channelnumber, and so on. The STT transmits information on the current weatherand time, and the RRT transmits information on the region anddeliberation committee for program rating. The EIT transmits informationon the events of a virtual channel (e.g., program title, program starttime, etc.). The DCCT/DCCSCT transmits information associated withautomatic channel change, and the MGT transmits version and PIDinformation of each table within the PSIP.

Each table within the above-described PSI/PSIP includes a basic unitreferred to as a “section”, and at least one or more sections arecombined to configure a table. For example, the VCT may be divided into256 sections. Herein, a single section may carry a plurality of channelinformation. However, the information on the virtual channel is notdivided into two or more sections. An example of multiplexing andtransmitting a traffic information message and a table associated with asystem information is given in the description of the present invention.

FIG. 6 illustrates a block view showing a general structure of a digitalbroadcast transmitting system according to an embodiment of the present,wherein a traffic information message and a table associated with thesystem information are multiplexed and transmitted. Referring to FIG. 6,the transmitting system includes a first multiplexer 311, a PSI/PSIPgenerator 312, and a second multiplexer 313. More specifically, forexample, the transmitting system may correspond to a broadcast station.In order words, the traffic information message is inputted to the firstmultiplexer 311 in a 188-byte transport stream (TS) packet unit. Herein,the traffic information message a traffic information application (e.g.,a CTT application) that is to be transmitted.

The TS packet is configured of a header part and a payload part. Herein,the header part includes information indicating the beginning of thedata and packet identification (PID) identifying the data partcorresponding to the payload part. And, the payload part includes atraffic information message that is intended to be transmitted. At thispoint, the PID within the header part may either correspond to anidentifier that can identify the data carried by the payload part as thetraffic information message among the enhanced data, or correspond to anidentifier that can identify the enhanced data. In case the PID of theheader can identify the traffic information message, the trafficinformation message may be extracted from the TS packet. On the otherhand, in case the PID of the header can identify the enhanced data, allTS packets identified as the enhanced data are received. Thereafter, thetraffic information message is extracted from the received enhanceddata. Furthermore, the TS packet which carries the traffic informationmessage may correspond either to a packetized elementary stream (PES)type or to a section type. In other words, either a PES type trafficinformation message may be configured as the TS packet, or a sectiontype traffic information message may be configured as the TS packet.

An example of the traffic information message being transmitted as thesection type will be described in the present invention. In thisembodiment of the present invention, the traffic information message isincluded in a digital storage media-command and control (DSM-CC)section, and the DSM-CC section is then configured as a 188-byte size TSpacket. Herein, the identifier of the TS packet configuring the DSM-CCsection is included in a data service table (DST). When transmitting theDST table, ‘0x95’ is assigned as a stream_type field value within aservice location descriptor of either the PMT or the VCT. Morespecifically, in the receiving system, when the stream_type field valueof the PMT or VCT is equal to ‘0x95’, this indicates that databroadcasting (i.e., enhanced data) including the traffic informationdata is being received. At this point, the traffic information data maybe transmitted by a data carousel method. Herein, the data carouselmethod refers to repeatedly transmitting the same data periodically.

Meanwhile, the PSI/PSIP generator 312 is an example of a systeminformation generator. The table that may be created by the PSI is atleast one of PMT, PAT, CAT, and NIT. And, the table that may be createdby the PSIP is at least one of VCT, STT, RRT, ETT, DCCT, DCCST, EIT, andMGT. The table created by the PSI/PSIP generator 312 includes a systeminformation so that the receiving system may parse and decode thetraffic information message. At this point, the receiving, system mayuse only the tables within the PSI, or only the tables within the PSIP,or a combination of tables within both the PSI and the PSIP, so as toparse and decode the traffic information message. At least the PAT andPMT of the PSI and at least the VCT of the PSIP is required for parsingand decoding the traffic information message. For example, the PAT mayinclude the system information transmitting the traffic informationmessage and the PID of the PMT corresponding to the traffic informationmessage (or program number). The PMT may include the PID of the TSpacket transmitting the traffic information message. The VCT may includethe PID of the TS packet transmitting the information of the virtualchannel, which transmits the traffic information message, and thetraffic information message.

Also, the present invention includes supplemental information associatedwith traffic information specifically indicating to which applicationthe traffic information message belonged and information specificallyindicating which information is included. The supplemental informationassociated with the traffic information may include service componentidentification information, application identification information,service information, and so on. The service information may includeservice name, service description, service logo, subscriber information,free text information, help information, and so on. Furthermore, suchsupplemental information may be included in a particular table withinthe PSI/PSIP either in a descriptor format or in a field format.

For simplicity of the description of the present invention, a descriptorincluding the supplemental information associated with the trafficinformation that is included in a particular table within the PSI/PSIPis referred to as a traffic information descriptor. Herein, the trafficinformation descriptor may also be referred to as a TPEG servicedescriptor. As described above, the term “traffic informationdescriptor” is only an example given to facilitate the understanding ofthe present invention. Therefore, any other term having the samefunction as the traffic information descriptor may also be appliedherein. Moreover, in the description of the present invention, theparticular table including the traffic information descriptor is definedas a traffic information providing table. Furthermore, the particulartable including the traffic information descriptor is defined as asystem information (SI) table wherein the traffic information descriptoris included.

FIG. 7 illustrates a syntax structure of traffic information descriptorsaccording to an embodiment of the present invention. Referring to FIG.7, the TPEG service descriptor may include a Descriptor_tag field, aDescriptor_length field, a Number_of_TPEG_Service_Components field, anda ‘for’ loop repetition statement. Herein, theNumber_of_TPEG_Service_Components field indicates the number of servicecomponents included in the TPEG service descriptor (or trafficinformation descriptor). And, the ‘for’ loop repetition statement isrepeated as much as the value of the Number_of_TPEG_Service_Componentsfield. The repetition statement may include a Service_Component_IDfield, an Application_ID field, and a service information field.

More specifically, the Descriptor_tag field is an 8-bit field, which isgiven a value that can uniquely identify the TPEG service descriptor. Inthe example of the present invention, a value of 0xAC is given as thetag value of the TPEG service descriptor. However, this is only anexample provided for an easier understanding of the present invention.Depending upon the design of the system designer, other kind of unusedtag values may be allocated to the Descriptor_tag field. TheDescriptor_length field is an 8-bit field, which indicates in byte unitsthe length starting from the Descriptor_length field to the end of thisfield.

The Service_component_ID (SCID) field is also an 8-bit field, whichindicates a value that can uniquely identify the service componentwithin a service. The SCID field may be decided by the service provider.Herein, a single service component substantially corresponds to a singlechannel within the TPEG stream. The Application_ID field is a 16-bitfield, which indicates a value that can uniquely identify eachapplication. More specifically, a unique application identifier (AID) isassigned to each traffic information application, and a new AID isallocated whenever a new application is developed (or created).

The service information field within the repetition statement mayinclude a Service_name field, a Service_description field, aService_logo field, a Subscriber_information field, aFree_text_information field, and a Help_information field. The length ofeach field within the service information field is variable and isindicates in the form of at least one of a text sequence, numbers, andgraphics. The Service_name field indicates the name of a service, whichallows the user to identify a particular service. For example, a servicename such as ‘TPEG service of broadcast company A’ may be included whenthe broadcast program is being transmitted. The Service_descriptionfield indicates a detailed description of the corresponding service.This field is for describing the service contents in more detail. Forexample, a service named “suburban public transportation information inthe southern urban area” may be included and transmitted. TheService_logo field indicates a service logo, so as to allow a service ora service provider to be identified visually. The service logo isgenerally transmitted in a bitmap format or any other image format.

The Subscriber_information field indicates the subscriber information.For example, information such as a user fee for limited (or restricted)service components and payment information may be included andtransmitted. The Free_text_information field indicates additionalinformation that is to be transmitted to the user. For example,information on an interruption (or suspension) of a service,cancellation of a particular information, and so on, may be included andtransmitted. And, the Help_information field indicates help informationwhich the user can refer to. For example, information such as Internetaddresses, telephone numbers, and so on may be included herein andtransmitted.

The order, location, and meaning of each field shown in FIG. 7 aremerely examples for facilitating the understanding of the presentinvention. And, since the order, location, and meaning of each field,and the number of field being additionally allocated can be adequatelymodified by anyone skilled in this field, the present invention is notlimited only to the examples set forth herein. Also, in the examplegiven in the present invention, the traffic information descriptor shownin FIG. 7 is included in at least one of the PMT of the PSI and the VCTof the PSIP and then transmitted.

More specifically, in the description of the present invention, anexample of applying the PMT of the PSI and the VCT of the PSIP as thetraffic information providing table. This indicates that thesupplemental information associated with the traffic information may betransmitted through the PMT and/or VCT of the descriptor or the field.Similarly, when supplemental information associated with the trafficinformation is described in a field format, it is apparent that thefields can be applied to at least one of the tables of the PMT of thePSI and the VCT of the PSIP. Herein, the process of including the PMTand/or the VCT in the traffic information descriptor may be eithermandatory or optional. Furthermore, whether the PMT and/or the VCTare/is mandatorily or optionally included is also merely an example ofthe present invention. Accordingly, the example does not limit the scopeand spirit of the present invention.

FIG. 8 illustrates an example of table that may include the trafficinformation descriptors of FIG. 7. More specifically, FIG. 8 showsexamples of the main descriptor types used in the PSI/PSIP table, thedescriptor tag values allocated to each descriptor, and the PSI/PSIPtables using at least one of the above-described descriptors. Referringto FIG. 8, a service location descriptor indicated as ‘S’ must alwaysexist in the VCT. More specifically, the service location descriptorcarries the audio PID and video PID of a broadcast program. Also, in acorresponding service each of the descriptors must be included in thetables indicated as ‘M (i.e., mandatory)’ and may or may not be includedin the tables indicated as ‘O (i.e., optionally)’.

For example, AC-3 audio descriptor is given a value of 0x81 as thedescriptor tag value and must indicate that it is used in the PMT andEIT. Furthermore, the TPEG service descriptor according to the exampleof the present invention is given a value of 0xAC the descriptor tagvalue and is marked as ‘mandatory (M)’ on the PMT and VCT. Theabove-described example is only proposed to simplify the description ofthe present invention. The TPEG service descriptor may also be marked as‘mandatory (M)’ or ‘optional (O)’ on at least one of the PMT and VCT.The 0xAC value given as the TPEG service descriptor tag value is alsoonly proposed as an example for facilitating the understanding of thepresent invention. Accordingly, depending upon the design of the systemdesigner, other unused tag values may also be assigned herein.

FIG. 9 illustrates a syntax structure on a virtual channel table (VCT)wherein the traffic information descriptors of FIG. 7 are includedaccording to an embodiment of the present invention. Herein, the syntaxstructure and its meaning correspond to those of a private section. TheVCT syntax of FIG. 9 is configured by including at least one of atable_id field, a section_syntax_indicator field, a private_indicatorfield, a section_length field, a transport_stream_id field, aversion_number field, a current_next_indicator field, a section_numberfield, a last_section_number field, a protocol_version field, and anum_channels_in_section field.

The VCT syntax further includes a first ‘for’ loop repetition statementthat is repeated as much as the num_channels_in_section field value. Thefirst repetition statement may include at least one of a short_namefield, a major_channel_number field, a minor_channel_number field, amodulation_mode field, a carrier_frequency field, a channel_TSID field,a program_number field, an ETM_location field, an access_controlledfield, a hidden field, a service_type field, a source_id field, adescriptor_length field, and a second ‘for’ loop statement that isrepeated as much as the number of descriptors included in the firstrepetition statement. Herein, the second repetition statement will bereferred to as a first descriptor loop for simplicity. The descriptordescriptors( ) included in the first descriptor loop is separatelyapplied to each virtual channel.

Furthermore, the VCT syntax may further include anadditional_descriptor_length field, and a third ‘for’ loop statementthat is repeated as much as the number of descriptors additionally addedto the VCT. For simplicity of the description of the present invention,the third repetition statement will be referred to as a seconddescriptor loop. The descriptor additional_descriptors( ) included inthe second descriptor loop is commonly applied to all virtual channelsdescribed in the VCT.

As described above, referring to FIG. 7, the table_id field indicates aunique identifier (or identification) (ID) that can identify theinformation being transmitted to the table as the VCT. Morespecifically, the table_id field indicates a value informing that thetable corresponding to this section is a VCT. For example, a 0xC8 valuemay be given to the table_id field.

The version_number field indicates the version number of the VCT. Thesection_number field indicates the number of this section. Thelast_section_number field indicates the number of the last section of acomplete VCT. And, the num_channel_in_section field designates thenumber of the overall virtual channel existing within the VCT section.Furthermore, in the first ‘for’ loop repetition statement, theshort_name field indicates the name of a virtual channel. Themajor_channel_number field indicates a ‘major’ channel number associatedwith the virtual channel defined within the first repetition statement,and the minor_channel_number field indicates a ‘minor’ channel number.More specifically, each of the channel numbers should be connected tothe major and minor channel numbers, and the major and minor channelnumbers are used as user reference numbers for the corresponding virtualchannel.

A virtual channel number is assigned to the traffic information messageaccording to the present invention, and the traffic information messagemay be transmitted through the assigned virtual channel. In this case,the short_name field indicates the name of the virtual channel throughwhich the traffic information message is transmitted. Themajor_channel_number/minor_channel_number field the number of thevirtual channel through which the traffic information message istransmitted. The program_number field is shown for connecting thevirtual channel having an MPEG-2 program association table (PAT) andprogram map table (PMT) defined therein, and the program_number fieldmatches the program number within the PAT/PMT. Herein, the PAT describesthe elements of a program corresponding to each program number, and thePAT indicates the PID of a transport packet transmitting the PMT. ThePMT described subordinate information, and a PID list of the transportpacket through which a program identification number and a separate bitsequence, such as video and/or audio data configuring the program, arebeing transmitted.

The source_id field indicates a program source connected to thecorresponding virtual channel. Herein, a “source” refers a particularsource such as a video image, data or sound. The value of the source_idfield corresponds to a unique value within the transport stream, whichtransmits the VCT. In an example according to the present invention, thetraffic information descriptor describing the supplemental informationassociated with traffic information (i.e., supplemental informationassociated with the CTT) is included in the first descriptor loop. Asdescribed above in the description of the VCT, it is apparent thatanyone skilled in the art can apply the example given in the presentinvention to other tables.

According to the present invention, there are two different methods ofdefining the PID of the VCT, which includes the traffic informationdescriptor. Herein, the PID of the VCT is a packet identifier (PID)required for identifying (or distinguishing) the VCT from the othertables. In the first method, the PID of the VCT according to the presentinvention may be set to depend upon the MGT. In this case, the receivingsystem cannot directly identify (or verify) the plurality of tables ofthe PSIP or PSI. Therefore, the VCT can be read only after the PIDdefined by the MGT is checked. Herein, the MGT is a table defining thePID, size, version number, and so on, of the plurality of tables. In thesecond method, the PID of the VCT according to the present invention maybe set to have a base PID value (i.e., a fixed PID value) that isindependent from the MGT. Unlike the first method, the second method ismore advantageous in that the VCT can be identified without having toverify every single PID of the MGT. Evidently, the agreement on the basePID should precede the transmitting system and the receiving system.

As described above, the PAT, PMT, VCT, MGT, DCCT, and so on, describingthe system information and supplemental information associated withtraffic information are generated by the PSI/PSIP generator 312. Herein,the PMT is provided to the first multiplexer 311, and the remainingtables excluding the PMT (i.e., PAT, VCT, MGT, DCCT, and so on) areprovided to the second multiplexer 313. The first multiplexer 311multiplexes the traffic information message, which includes informationon the traffic information application that is to be transmitted (e.g.,CTT application), with the PMT, which is generated from the PSI/PSIPgenerator 312, to a 188-byte transport stream (TS) packet. Thereafter,the multiplexed message and table are outputted to the secondmultiplexer 313. The second multiplexer 313 multiplexes the output ofthe first multiplexer 311 with the tables outputted from the PSI/PSIPgenerator 312 to a 188-byte transport stream (TS) packet. Subsequently,the multiplexed message and table are outputted for additional coding.

An example of providing the PMT to the first multiplexer 311 andproviding the remaining tables to the second multiplexer 313 is proposedin the description of the present invention. However, the presentinvention may also be designed to have a single multiplexer byintegrating the first multiplexer 311 and the second multiplexer 313.The traffic information data that are outputted from the multiplexer ofFIG. 6 for additional coding include a traffic information message andPSI/PSIP tables associated with the traffic information messagemultiplexed therein. Also, at least one of the above-described tables(e.g., PMT, VCT) may include a traffic information descriptor shown inFIG. 7.

Hereinafter, the coding and transmitting processes of the trafficinformation data will be described in detail according to first, second,and third embodiments of the present invention. By performing theadditional coding process on the traffic information data, robustnesscan be provided to the traffic information data, such as the CTT data.Thus, the data can respond swiftly and appropriately to the channelenvironment that undergoes fast and frequent change.

First Embodiment

FIG. 10 illustrates a block view showing a structure of a digitalbroadcast transmitting system according to a first embodiment of thepresent invention. Referring to FIG. 10, the digital broadcasttransmitting system includes an E-VSB pre-processor 401, a packetmultiplexer 402, a data randomizer 403, a RS encoder 404, a datainterleaver 405, a backward compatibility processor 406, a trellisencoder 407, a frame multiplexer 408, a pilot inserter 409, a VSBmodulator 410, and a RF up-converter 411. Herein, as shown in FIG. 11,the E-VSB pre-processor 401 includes an E-VSB randomizer 421, a RS frameencoder 422, an E-VSB block processor 423, a group formatter 424, a datadeinterleaver 425, and a packet formatter 426.

In the digital broadcast transmitting system having the above describedstructure, the main data are inputted to the packet multiplexer 402. Onthe other hand, the traffic information data are inputted to the E-VSBpre-processor 401, which performs additional coding processes so as toenable the traffic information data to respond quickly with robustnessagainst noise and channel change. The E-VSB randomizer 421 of the E-VSBpre-processor 401 receives the traffic information data, therebyrandomizing the received data and outputting the randomized data to theRS frame encoder 422. Herein, since the E-VSB randomizer 421 randomizesthe traffic information data, the randomizing process of data randomizer403 on the traffic information in a later process may be omitted.

The RS frame encoder 422 receives the randomized traffic informationdata and performs at least one of an error correction coding process andan error detection coding process on the received data. Accordingly, byproviding robustness to the traffic information data, the data canscatter group error that may occur due to a change in the frequencyenvironment. Thus, the data can respond appropriately to the frequencyenvironment which is very poor and liable to change. The RS framemultiplexer 422 also includes a process of mixing in row units many setsof traffic information data each having pre-determined size. Byperforming an error correction coding process on the inputted trafficinformation data, the RS frame encoder 422 adds data required for theerror correction and, then, performs an error detection coding process,thereby adding data required for the error detection process.

The error correction coding uses the RS coding method, and the errordetection coding uses the cyclic redundancy check (CRC) coding method.When performing the RS coding process, parity data required for errorcorrection are generated. And, when performing the CRC coding process,CRC data required for error detection are generated. More specifically,the RS frame encoder 422 identifies the traffic information data byunits of a predetermined length (A). Then, a plurality of (A)-lengthunits of traffic information data is grouped so as to form (orconfigure) a RS frame. Thereafter, an RS coding process is performed inat least one of a row direction and a column direction on the newlyconfigured RS frame. In the present invention, the predetermined lengthunit (A) corresponds to 187 bytes.

If the inputted traffic information data correspond to a 188-byte unitMPEG transport stream (TS) packet, the first MPEG synchronization byteis removed, so as to form a 187-byte unit packet. Herein, the MPEGsynchronization byte is removed because all traffic information datapackets are given the same value. The MPEG synchronization byte may alsobe removed during the randomizing process on the E-VSB randomizer 421.In this case, the process of removing the MPEG synchronization byteperformed by the RS frame encoder 422 is omitted. More specifically, ifthe inputted traffic information data does not include a fixed byte thatcan be removed, or if the length of the inputted packet is not 187bytes, the inputted traffic information data is distinguished by187-byte units. Thereafter, a plurality of 187-byte units of trafficinformation data is grouped so as to form (or configure) a RS frame.Thereafter, an RS coding process is performed in at least one of a rowdirection and a column direction on the newly configured RS frame.

Depending upon the channel situation between the transmission and thereception, an error may be included in the RS frame. When such erroroccurs, the CRC data (or CRC code or CRC checksum) may be used forchecking whether an error exists by each row unit. In order to generate(or create) the CRC checksum, the RS frame encoder 422 performs CRCcoding on the RS-coded traffic information data. The CRC checksumcreated by the CRC coding process may be used for notifying whether adamage has occurred by an error while the traffic information data arebeing transmitted through a channel. In the present invention, errordetection coding method other than the CRC coding method may be used.Alternatively, an error correction coding method may be used in order toenhance the overall error correction ability of the receiving end.

The traffic information data sets RS-coded and CRC-coded, as describedabove, are outputted to the E-VSB block processor 423. The E-VSB blockprocessor 423 codes the RS-coded and CRC-coded traffic information dataat a coding rate of G/H (wherein G and H are integers, and G<H) and thenoutputs the G/H-rate coded data to the group formatter 424. For example,if 1 bit of the input data is coded to 2 bits and outputted, then G isequal to 1 and H is equal to 2 (i.e., G=1 and H=2). Alternatively, if 1bit of the input data is coded to 4 bits and outputted, then G is equalto 1 and H is equal to 4 (i.e., G=1 and H=4).

An example performing a coding process at a coding rate of 1/2 (alsoreferred to as a 1/2-rate coding process) or a coding process at acoding rate of 1/4 (also referred to as a 1/4-rate coding process) onthe traffic information data is given in the description of the presentinvention. More specifically, in case of performing the 1/2-rate codingprocess, the E-VSB block processor 423 receives 1 bit and codes thereceived 1 bit to 2 bits (i.e., 1 symbol). Then, the E-VSB blockprocessor 423 outputs the processed 2 bits (or 1 symbol). On the otherhand, in case of performing the 1/4-rate coding process, the E-VSB blockprocessor 423 receives 1 bit and codes the received 1 bit to 4 bits(i.e., 2 symbols). Then, the E-VSB block processor 423 outputs theprocessed 4 bits (or 2 symbols). At this point, in case of performingthe 1/4-rate coding process, the symbol coded at a 1/2 coding rate maybe repeated twice so as to output symbols, or the input data may becoded twice at a 1/2 coding rate so as to output 2 symbols.

The 1/4-rate coding process may provide more enhanced error correctionability, due to the higher coding rate as compared to the 1/2-ratecoding process. For this reason, the data coded at a 1/4 coding rate bythe group formatter 424 in a later process are allocated to locations(or positions) in which the channel may affect the performance. On theother hand, the data coded at a 1/2 coding rate are allocated tolocations having better performance. Thus, a difference in performancemay be decreased. The above-mentioned 1/2-coding rate and 1/4-codingrate are only exemplary embodiments proposed in the description of thepresent invention, and the coding rate may vary depending upon eitherthe selection of the coded symbols or the number of repetition.

The group formatter 424 inserts the traffic information data outputtedfrom the E-VSB block processor 423 in a corresponding area within a datagroup formed according to a pre-defined rule. Also, the group formatter424 inserts various place holders related to data interleaving or knowndata sets to a corresponding area within the data group. At this point,the data group may be described by at least one hierarchical area. And,depending upon the characteristic of each hierarchical area, the datatype being allocated to each area may also vary.

FIG. 12A illustrates a data structure of data groups prior to the datadeinterleaving process, and FIG. 12B illustrates a data structure ofdata groups after the data deinterleaving process. FIG. 12A illustratesan example of a data group within a data structure prior to the datadeinterleaving, the data group being divided into three hierarchicalareas: a head area, a body area, and a tail area. Accordingly, in thedata group that is inputted for the data deinterleaving process, dataare first inputted to the head area, then inputted to the body area, andinputted finally to the tail area. The three areas described above areonly exemplary to facilitate the understanding of the present invention.Depending upon the design of the system designer, the areas may bedescribed in a smaller number of areas or a larger number of areas.Further, the data being inserted in each area may also vary. Therefore,the present invention is not limited only to the example proposedherein.

As described above, the head, body, and tail areas have been given as anexample to simplify the description of the present invention.Additionally, in the example shown in FIG. 12A, the data group is set tohave head, body, and tail areas so that the body area is defined as thearea which is not mixed with the main data area within the data group.The data group is divided into a plurality of areas so that each areamay be used differently. More specifically, the area that is notinterfered by the main data has a highly resistant receiving performanceas compared to the area that is interfered by the main data.Furthermore, when using a system inserting and transmitting the knowndata to the data group, and when a long and continuous set of known datais to be inserted periodically in the enhanced data, a predeterminedlength of known data may be periodically inserted in the body area.However, since the main data may be mixed in the head and tail areas, itis difficult to periodically insert the known data, and it is alsodifficult to insert a long and continuous set of known data.

Assuming that the data group is allocated to a plurality of hierarchicalareas, as shown in FIG. 12A, the above-described E-VSB block processor423 may code the data that are to be inserted in each area, according tothe characteristic of each hierarchical area, at different coding rates.In the example of the present invention, the receiving system usesdifferent coding rates based on areas in which it is assumed thatperformance may vary after performing an equalization process usingchannel information that may be used for channel equalization.

For example, the traffic information data that are to be inserted in thebody area are 1/2-rate coded by the E-VSB block processor 423, and such1/2-rate coded traffic information data are inserted to the body area bythe group formatter 424. Additionally, the traffic information data thatare to be inserted in the head and tail areas are 1/4-rate coded by theE-VSB block processor 423. Herein, the 1/4-rate coding provides greatererror correction performance as compared to 1/2-rate coding. Thereafter,1/4-rate coded traffic information data are inserted to the head andtail areas by the group formatter 424. Alternatively, the trafficinformation data that are to be inserted in the head and tail areas maybe coded by the E-VSB block processor 423 at a coding rate providingmore efficient error correction performance. Subsequently, such codedtraffic information data are inserted in the head and tail areas by theE-VSB block processor 423, or such coded data may be stored in a reservearea for future usage.

As shown in FIG. 12A, apart from the traffic information data coded andoutputted from the E-VSB block processor 423, the group formatter 424also inserts an MPEG header place holder, a non-systematic RS parityplace holder, and a main data place holder in relation with the datadeinterleaving. Referring, to FIG. 12A, the main data place is allocatedbecause the traffic information data and the main data are alternatelymixed in the head and tail areas based upon the input of the datadeinterleaver. In the output data that have been data deinterleaved, theplace holder for the MPEG header is allocated to the very beginning ofeach packet.

The group formatter 424 either inserts the known data generated by apre-decided method in a corresponding area, or inserts a known dataplace holder in a corresponding area so as to insert the known data in alater process. Moreover, a place holder for initializing the trellisencoder 407 is inserted in the corresponding area. For example, theinitialization data place holder may be inserted in front of the knowndata sequence. The output of the group formatter 424 is inputted to thedata interleaver 425. The data deinterleaver 425 performs an inverseprocess of the data interleaver on the data within the data group andthe place holder outputted from the group formatter 424. And, then, thedata deinterleaver 425 outputs the deinterleaved data to the packetformatter 426. More specifically, when the data within the data groupand the place holder the configuration shown in FIG. 12A aredeinterleaved by the data deinterleaver 425, the data group beingoutputted to the packet formatter 426 has the structure (orconfiguration) shown in FIG. 12B.

Among the deinterleaved and inputted data, the packet formatter 426removes the main data place holder and the RS parity place holder thathave been allocated for the deinterleaving process. Then, the packetformatter 426 groups the remaining portion of the input data and insertsthe remaining data to the 4-byte MPEG header place holder in the MPEGheader. Furthermore, when the known data place holder is inserted by thegroup formatter 424, the packet formatter 426 may insert the known datain the known data place holder. Alternatively, the known data placeholder may be directly outputted without any modification for thereplacement insertion in a later process.

Thereafter, the packet formatter 426 configures the data within the datagroup packet that is formatted as described above, as a 188-byte unittraffic information data packet. Then, the packet formatter 426 providesthe configured 188-byte unit traffic information data packet to thepacket multiplexer 402. The packet multiplexer 402 multiplexes the188-byte traffic information data packet and the main data packetoutputted from the packet formatter 426 according to a pre-definedmultiplexing method. Then, the multiplexed packets are outputted to thedata randomizer 403. The multiplexing method may be altered or modifiedby various factors in the design of the system.

In a multiplexing method of the packet multiplexer 402, a trafficinformation data burst section and a main data section are distinguished(or identified) along a time axis, then the two sections are set to berepeated alternately. At this point, in the traffic information databurst section, at least one of the data groups may be transmitted, andonly the main data may be transmitted in the main data section thetraffic information data burst section, the main data may also betransmitted. When the traffic information data are transmitted in theabove-described burst structure, the digital broadcast receiving systemreceiving only the traffic information data may turn on the power onlyduring the data burst section. Alternatively, in the main data sectionwhereby only the main data are transmitted, the power is turned offduring the main data section, thereby preventing the main data frombeing received. Thus, excessive power consumption of the digitalbroadcast receiving system may be reduced or prevented. As describedabove, the packet multiplexer 402 receives the main data packet and thedata group, which is outputted from the packet formatter 426, andtransmits the received packets in a burst structure.

When the inputted data correspond to the main data packet, the datarandomizer 403 performs a randomizing process identical to that of theconventional randomizer. More specifically, the MPEG synchronizationbyte within the main data packet is discarded (or deleted). Then, theremaining 187 bytes are randomized by using a pseudo random bytegenerated from within the data randomizer 403. Subsequently, therandomized data bytes are outputted to the RS encoder 404.

However, when the inputted data correspond to the traffic informationdata packet, the MPEG synchronization byte among the 4 bytes inserted inthe traffic information data packet by the packet formatter 426 isdiscarded (or deleted) and only the remaining 3 bytes are randomized.The remaining portion of the traffic information data excluding the MPEGheader is not randomized and outputted directly to the RS encoder 404.This is because a randomizing process has already been performed on thetraffic, information data by the E-VSB randomizer 421. The RS encoder404 RS-codes the data randomized by the data randomizer 403 or the databypassing the data randomizer 403. Then, the RS encoder 404 adds a20-byte RS parity to the coded data, thereby outputting theRS-parity-added data to the data interleaver 405.

At this point, if the inputted data correspond to the main data packet,the RS encoder 404 performs a systematic RS-coding process identical tothat of the conventional. ATSC VSB system on the inputted data, therebyadding the 20-byte RS parity at the end of the 187-byte data.Alternatively, if the inputted data correspond to the trafficinformation data packet, each place of the 20 parity bytes is decidedwithin the packet. Thereafter, the 20 bytes of RS parity gained byperforming the non-systematic RS-coding are respectively inserted in thedecided parity byte places. The data interleaver 405 receives the datahaving the parity added by the RS encoder 404 and interleaves thereceived data. Thereafter, the data interleaver 405 outputs theinterleaved data to the backward compatibility processor 406 and thetrellis encoder 407. Herein, the data interleaver 405 corresponds to abyte unit convolutional interleaver.

Meanwhile, a memory within the trellis encoder 407 should first beinitialized in order to allow the output data of the trellis encoder 407so as to become the known data defined based upon an agreement betweenthe receiver and the transmitter. More specifically, the memory of thetrellis encoder 407 should first be initialized before the known datasequence being inputted is trellis-encoded. At this point, the beginningof the known data sequence that is inputted corresponds to theinitialization data place holder inserted by the group formatter 424 andnot the actual known data. Therefore, a process of generatinginitialization data right before the trellis-encoding of the known datasequence being inputted and a process of replacing the initializationdata place holder of the corresponding trellis encoder memory with thenewly generated initialization data are required. This is to ensure thebackward-compatibility with the conventional receiving system.

The trellis memory initialization data generated to replace theinitialization data place holder are decided based upon the currentstatus of the memory within the trellis encoder 407 and the desiredinitialization status. Further, due to the replaced initialization data,a process of recalculating the RS parity of the corresponding datapacket and a process of replacing the newly calculated RS parity withthe RS parity outputted from the data interleaver 405 are required.Therefore, the backward compatibility processor 406 receives the trafficinformation data packet including the initialization data place holderthat is to be replaced with the initialization data from the datainterleaver.

Subsequently, the backward compatibility processor 406 receives theinitialization data from the trellis encoder 407. Then, the backwardcompatibility processor 406 calculates a new non-systematic RS parityand outputs the newly calculated non-systematic RS parity to the trellisencoder 407. Thereafter, the trellis encoder 405 selects the output ofthe data interleaver 405 as the data within the traffic information datapacket including the initialization data place holder that is to bereplaced. The trellis encoder 405 also selects the output of thebackward compatibility processor 406. Accordingly, the trellis encoder405 trellis-encodes the selected outputs by symbol units. Morespecifically, the trellis encoder 407 trellis-encodes the initializationdata instead of the initialization data place holder included in thetraffic information data packet which has been inputted.

Meanwhile, when the main data packet is inputted or when the trafficinformation data packet is inputted, wherein the traffic informationdata packet does not include the initialization data place holder thatis to be replaced, the trellis encoder 407 selects the data outputtedfrom the data interleaver 405 and the RS parity, thereby performing atrellis-encoding process by symbol units. Then, the data trellis-encodedby the trellis encoder 407 are inputted to the frame multiplexer 408.The frame multiplexer 408 inserts field and segment synchronizationsignals in the output of the trellis encoder 407 and outputs theprocessed data to the pilot inserter 409. The pilot inserter 409 adds apilot signal to the output symbol sequence of the frame multiplexer 408.The pilot-added symbol sequence is modulated to a 8VSB, signal of anintermediate frequency band and, then, converted to a RF band signal,thereby being transmitted through the antenna.

Meanwhile, the embodiment shown in FIG. 11 for the components andpositioning of the components of the E-VSB pre-processor 401 is, merelyan example for the simplicity of the description of the presentinvention. According to a second embodiment of the present invention,the E-VSB pre-processor 401 includes, a RS frame encoder, an E-VSBrandomizer, an E-VSB block processor, a group formatter, a datainterleaver, and a packet formatter. The difference between the secondembodiment and the E-VSB pre-processor shown in FIG. 11 is thepositioning order of the RS frame multiplexer and the E-VSB randomizer.More specifically, in the second embodiment of the present invention, RSframe coding is first performed on the traffic information data, andthen the data randomizing process is performed. Apart from this detail,the remaining structure of the second embodiment is identical to theembodiment shown in FIG. 11. Therefore, a detailed description of thesame will be omitted for simplicity.

In a third embodiment of the present invention, the E-VSB pre-processor401 includes a RS frame encoder, an E-VSB randomizer, a group formatter,an E-VSB block processor, a data interleaver, and a packet formatter.The difference between the third embodiment and the E-VSB pre-processorshown in FIG. 11 is the positioning order of the RS frame multiplexerand the E-VSB randomizer and, also, the positioning order of the groupformatter and the E-VSB block processor. More specifically, in E-VSBpre-processor according to the third embodiment of the presentinvention, RS frame coding is first performed on the traffic informationdata, and then the data randomizing and byte expansion processes areperformed. Thereafter, group formatting, E-VSB block processing, datarandomizing, and packet formatting processes are sequentially performedon the byte-expanded traffic information data.

In this case, since the group formatter is positioned before the E-VSBblock processor, a byte expansion process needs to be performed beforethe group formatter in order to correspond to the coding process of theE-VSB block processor, thereby enabling the group formatter to operatewithout trouble. Therefore, the E-VSB randomizer not only randomizes thetraffic information data but also performs byte expansion by insertingnull data bits. Furthermore, the E-VSB block processor performs one of a1/2-rate coding process and a 1/4-rate coding process on only the validdata of the byte-expanded traffic information data, which correspond tothe data bits having the actual information. As described above, theE-VSB pre-processor 401 performing additional coding processes on thetraffic information data may be applied in various methods. Thus, thepresent invention is not limited only to the examples given in thedescription set forth herein.

Second Embodiment

FIG. 13 illustrates a block view showing a structure of a digitalbroadcast transmitting system according to a second embodiment of thepresent invention. Referring to FIG. 13, the digital broadcasttransmitting system includes an E-VSB pre-processor 501, a packetmultiplexer 502, a data randomizer 503, an E-VSB post-processor 504, aRS encoder 505, a data interleaver 506, a backward compatibilityprocessor 507, a trellis encoder 508, a frame multiplexer 509, a pilotinserter 510, a VSB modulator 511, and a RF up-converter 512. Herein, asshown in FIG. 14, the E-VSB pre-processor 501 includes a RS frameencoder 521, an E-VSB randomizer 522, a group formatter 523, a datadeinterleaver 524, and a packet formatter 525. Further, as shown in FIG.15, the E-VSB post-processor 504 includes RS parity place holderinserter 531, data interleaver 532, an E-VSB block processor 533, datadeinterleaver 534, and a RS parity place holder remover 535.

In the digital broadcast transmitting system according to the secondembodiment of the present invention having the above describedstructure, the main data are inputted to the packet multiplexer 502. Onthe other hand, the traffic information data are inputted to the E-VSBpre-processor 501, which performs additional coding processes so as toenable the traffic information data to respond quickly with robustnessagainst noise and channel change.

The RS frame encoder 521 of the E-VSB pre-processor 501 receives therandomized traffic information data and performs at least one of anerror correction coding process and an error detection coding process onthe received data. Accordingly, by providing robustness to the trafficinformation data, the data can scatter group error that may occur due toa change in the frequency environment. Thus, the data can respondappropriately to the frequency environment which is very poor and liableto change. The RS frame multiplexer 521 also includes a process ofmixing in row units many sets of traffic information data each havingpre-determined size. The error correction coding uses the RS codingmethod, and the error detection coding uses the cyclic redundancy check(CRC) coding method. When performing the RS coding process, parity datarequired for error correction are generated. And, when performing theCRC coding process, CRC data required for error detection are generated.

In the RS frame encoder 521, the process of creating the RS framecreating process and the process of performing error correction codingand error detection coding on the created RS frame are identical tothose of the RS frame encoder 422 shown in FIG. 11. Therefore, adetailed description of the same will be omitted for simplicity. Thetraffic information data coded by the RS frame encoder 521 are inputtedto the E-VSB randomizer/byte expander 522. The E-VSB randomizer/byteexpander 522 receives the coded traffic information data and performsdata randomizing and byte expansion processes thereon.

At this point, since the E-VSB randomizer/byte expander 522 alreadyperforms a randomizing process on the traffic information data, theprocess of randomizing the traffic information by the data randomizer503 at a later end may be omitted for simplicity. Further, the order ofperforming the data randomizing process and the byte expansion processmay be altered. More specifically, the byte expansion process may beperformed after the data randomizing process. Alternatively, the datarandomizing process may be performed after the byte expansion process.The order may be selected while taking into consideration the overallsystem and its structure.

The byte expansion may differ depending upon the coding rate of theE-VSB block processor 533 within the E-VSB post-processor 504. Morespecifically, when the coding rate of E-VSB block processor 533 is G/H,the byte expander expands G bytes to H bytes (wherein G and H areintegers, and G<H). For example, if the coding rate if 1/2, 1 data byteis expanded to 2 data bytes. Alternatively, if the coding rate if 1/4, 1data byte is expanded to 4 data bytes. Then, the traffic informationdata outputted from the E-VSB randomizer/byte expander 522 is inputtedto the group formatter 523. The operations of the group formatter 523,data deinterleaver 524, and the packet formatter 525 within the E-VSBpre-processor 501 are similar to those the group formatter 424, datadeinterleaver 425, and the packet formatter 426 within the E-VSBpre-processor 401 shown in FIG. 10. Therefore, a detailed description ofthe same will be omitted for simplicity.

The traffic information data packet pre-processed by the E-VSBpre-processor 501 is inputted to the packet multiplexer 502 so as to bemultiplexed with the main data packet. The data multiplexed andoutputted from the packet multiplexer 502 are data randomized by thedata randomizer 501 and, then, inputted to the E-VSB post-processor 504.Herein, the operations of the packet multiplexer 502 and data randomizer503 are identical to those shown in FIG. 10, and therefore a detaileddescription of the same will be omitted for simplicity. Hereinafter, theE-VSB post-processor 504 will now be described in detail.

More specifically, the data randomized by the data randomizer 503 orbypassing the data randomizer 503 are inputted the RS parity placeholder inserter 531 of the E-VSB post-processor 504. When the inputteddata correspond to a 187-byte main data packet, the RS parity placeholder inserter 531 inserts a 20-byte RS parity place holder at the backof the 187-byte data, thereby outputting the processed data to the datainterleaver 532. Alternatively, when the inputted data correspond to a187-byte traffic information data packet, the RS parity place holderinserter 531 inserts a 20-byte RS parity place holder within the datapacket in order to perform a non-systematic RS-coding process in a laterend. Thereafter, in the remaining portion of the 187 byte places bytesare inserted in the traffic information data packet, which are thenoutputted to the data interleaver 532.

The data interleaver 532 performs a data interleaving process on theoutput of the RS parity place holder inserter 531 and, then, outputs theprocessed data to the E-VSB block processor 533. The E-VSB blockprocessor 533 performs additional coding processes on the valid dataamong the traffic information data being outputted from data interleaver532. For example, if 1 byte has been expanded to 2 bytes by insertingnull bits between data bits from the E-VSB randomizer/byte expander 522,the E-VSB block processor 533 1/2-rate codes only the valid data bitamong the symbol configured of a null bit and a valid data bit and,then, outputs the processed data. On the other hand, if 1 byte has beenexpanded to 4 bytes by inserting null bits between data bits from theE-VSB randomizer/byte expander 522, the E-VSB block processor 5331/4-rate codes only the valid data bit among the symbol configured of 3null bits and 1 valid data bit and, then, outputs the processed data.

Either the main data or the RS parity place holder directly bypasses theE-VSB randomizer/byte expander 522. Also, the known data and theinitialization data place holder may directly bypass the E-VSBrandomizer/byte expander 522. In case of the known data place holder,the known data generated from the E-VSB block processor 533 may beoutputted instead of the known data place holder. The data being coded,replaced, and bypassed from the E-VSB block processor 533 are inputtedto the data deinterleaver 534. The data deinterleaver 534 performs aninverse process of the data interleaver 532, whereby a datadeinterleaving process is performed on the input data, which are thenoutputted to the RS parity place holder remover 535.

The RS parity place holder remover 535 removes the 20-byte RS parityplace holder inserted by the RS parity place holder inserter 531 for theoperations of the data interleaver 532 and the data deinterleaver 534and, then, outputs the processed data to the RS encoder 505. At thispoint, if the inputted data correspond to main data packet, the last 20bytes of RS parity place holders are removed from the 207 bytes of themain data packet. Alternatively, if the inputted data correspond to thetraffic information data packet, the 20 bytes of RS parity place holdersare removed from the 207 bytes of the traffic information data packet inorder to perform the non-systematic RS-coding process.

As another embodiment of the E-VSB post-processor 504, if the inputteddata correspond to the 187-byte main data packet, the RS parity placeholder inserter 531 may perform a systematic RS-coding process so as toinsert a 20-byte RS parity at the end of the 187-byte main data.Accordingly, the RS parity place holder inserter 531 removes the last 20bytes of RS parity from the 207 bytes of the main data packet.Meanwhile, the RS encoder 505, the data interleaver 506, the backwardcompatibility processor 507, the trellis encoder 508, the framemultiplexer 509, the pilot inserter 510, the VSB modulator 511, and theRF up-converter 512 which are provided behind the E-VSB post-processor504 are identical to those shown in FIG. 10. Therefore, a detaileddescription of the same will be omitted for simplicity.

Third Embodiment

FIG. 16 illustrates a block view showing a structure of a digitalbroadcast transmitting system according to a third embodiment of thepresent invention. Referring to FIG. 16, the digital broadcasttransmitting system includes an E-VSB pre-processor 601, a packetmultiplexer 602, a data randomizer 603, a RS encoder 604, a datainterleaver 605, an E-VSB post-processor 606, a backward compatibilityprocessor 607, a trellis encoder 608, a frame multiplexer 609, a pilot,inserter 610, a VSB modulator 611, and a RF up-converter 612.

In the digital broadcast transmitting system according to the thirdembodiment of the present invention having the above describedstructure, the main data are inputted to the packet multiplexer 602. Onthe other hand, the traffic information data are inputted to the E-VSBpre-processor 601, which performs additional coding processes so as toenable the traffic information data to respond quickly with robustnessagainst noise and channel change. The structure and operation of eachcomponent of the E-VSB pre-processor 601 are identical to those of theE-VSB pre-processor 501 shown in FIG. 14. Therefore, a detaildescription of the same will be omitted for simplicity.

The traffic information data packet pre-processed by the E-VSBpre-processor 601 is inputted to the packet multiplexer 602 so as to bemultiplexed with the main data packet. The multiplexed data outputtedfrom the packet multiplexer 602 are data randomized by the datarandomizer 603 and, then, inputted to the RS encoder 604. The packetmultiplexer 602 multiplexes the main data packet and the trafficinformation data packet according to a pre-defined multiplexing rule. Atthis point, the main data packet and the traffic information data packetmay be multiplexed to have burst structures as shown in FIG. 10.Furthermore, if the traffic information data have been data randomizedby the E-VSB pre-processor 601, then the data randomizing process on thetraffic information data performed by the data randomizer 603 may beomitted.

The RS encoder 604 RS-codes the data being randomized from or bypassingthe data randomizer 603, thereby adding a 20-byte RS parity andoutputting the processed data to the data interleaver 605. At thispoint, if the inputted data correspond to the main data packet, the RSencoder 604 performs a systematic RS-coding process identical to that ofthe conventional ATSC VSB system on the input data, thereby adding a20-byte RS parity at the end of the 187-byte data. Conversely, if theinputted data correspond to the traffic information data packet, the RSencoder 604 first decides 20 parity byte places and, then, performs anon-systematic RS-coding process on the decided parity byte places,thereby inserting the 20 bytes of non-systematic RS parity in thetraffic information data packet.

The non-systematic coding process is performed on the trafficinformation data packet because, when the value of the trafficinformation data is changed by the E-VSB post-processor 606, the processof which will be described in detail in a later process, the RS parityis required to be recalculated. And, at this point, the parity bytesshould be outputted later than the traffic information data bytes at theoutput end of the data interleaver 605. The data interleaver 605receives the data having parity added thereto by the RS encoder 604.Then, after performing an interleaving process, the data interleaver 605outputs the processed data to the E-VSB post-processor 606 and thebackward compatibility processor 607. Herein, the data interleaver 605receives the RS parity newly recalculated and outputted from thebackward compatibility processor 607, thereby outputting the received RSparity instead of non-systematic RS parity which is not yet outputted.

The E-VSB post-processor 606 performs additional coding processes insymbol units only on the traffic information data being outputted fromthe data interleaver 605. For example, if 1 byte has been expanded to 2bytes by inserting null bits between data bits from the E-VSBpre-processor 606, the E-VSB post-processor 606 1/2-rate codes only thevalid data bit among the symbol configured of a null bit and a validdata bit and, then, outputs the processed data. On the other hand, if 1byte has been expanded to 4 bytes by inserting null bits between databits from the E-VSB pre-processor 601, the E-VSB post-processor 6061/4-rate codes only the valid data bit among the symbol configured ofnull bits and 1 valid data bit and, then, outputs the processed data.

The main data or the RS parity being outputted from the data interleaver605 directly bypass (or bypasses) the E-VSB post-processor 606.Moreover, the known data and initialization data place holder alsodirectly bypass (or bypasses) the E-VSB post-processor 606. At thispoint, the known data place holder may be replaced with the known datagenerated from the E-VSB post-processor 606 and then outputted.Furthermore, the E-VSB post-processor 606 generates initialization dataso as to initialize the memory within the trellis encoder 608 to adecided status at the beginning of a known data sequence. Thereafter,the initialization data generated from the E-VSB post-processor 606 isoutputted instead of the initialization data place holder. Accordingly,the value of the memory within the trellis encoder 608 should bereceived from the E-VSB post-processor 606.

The backward compatibility processor 607 calculates the 20-bytenon-systematic RS parity corresponding to the traffic information datapacket configured on 187 data bytes and outputted from the E-VSBpost-processor 606. Subsequently, the calculated non-systematic RSparity is outputted to the data interleaver 605. The data interleaver605 receives the RS parity bytes calculated and outputted from thebackward compatibility processor 607 and, then, outputs the received RSparity bytes instead of the non-systematic RS parity. Herein, thebackward compatibility processor 607 performs a non-systematic RS-codingprocess because the E-VSB post-processor 606 changes the values of thetraffic information data and the initialization data place holder.Accordingly, when a decoding process is performed by the conventional.ATSC VSB receiver, a decoding error may be prevented. In other words,this process is performed to provide backward compatibility to theconventional ATSC VSB receiver.

The data that are additionally coded and replaced by the E-VSBpost-processor 606 and that bypass the E-VSB post-processor 606 areinputted to the trellis encoder 608 so as to be trellis-encoded.Thereafter, the trellis-encoded data sequentially pass through the framemultiplexer 609, the pilot inserter 610, the VSB modulator 611, and theRF up-converter 612. Meanwhile, according to another embodiment of thepresent invention, initialization data, which are generated forinitializing a memory within the trellis encoder 608, are generated fromthe trellis encoder 608 instead of the E-VSB post-processor 606. In thiscase, the backward compatibility processor 607 receives a trafficinformation data packet from the E-VSB post-processor 606 in order tocalculate the parity value. Herein, the traffic information data packetincludes an initialization data place holder that is to be replaced bythe initialization data. Further, the backward compatibility processor607 receives the initialization data from the trellis encoder 608.Thereafter, the calculated non-systematic RS parity is outputted to thetrellis encoder 608. The remaining processes that may follow areidentical to those shown in FIG. 10. Therefore, a detailed descriptionof the same will be omitted for simplicity. Furthermore, the framemultiplexer 609, the pilot inserter 610, the VSB modulator 611, and theRF up-converter 612 are also identical to those shown in FIG. 10.Therefore, a detailed description of the same will also be omitted forsimplicity.

FIG. 17 illustrates a block view of a digital broadcast receiving systemaccording to an embodiment of the present invention. More specifically,FIG. 17 illustrates a block view showing an example of a digitalbroadcast receiving system that can receive traffic information databeing transmitted from a transmitting system and that demodulates andequalizes the received data, thereby recovering the processed data toits initial state. Referring to FIG. 17, the receiving system includes atuner 701, a demodulator 702, a demultiplexer 703, an audio decoder 704,a video decoder 705, a native TV application manager 706, a channelmanager 707, a channel map 708, a first memory 709, a data decoder 710,a second memory 711, a system manager 712, a data broadcastingapplication manager 713, and a GPS module 714. Herein, the first memory709 corresponds to a non-volatile memory (NVRAM) (or a flash memory).

The tuner 701 tunes a frequency of a particular channel through any oneof an antenna, a cable, and a satellite, thereby down-converting thetuned frequency to an intermediate frequency (IF) signal. Thereafter,the down-converted signal is outputted to the demodulator 702. At thispoint, the tuner 701 is controlled by the channel manager 707. Theresult and strength of the broadcast signal corresponding to the tunedchannel are reported to the channel manager 707. Herein, the data beingreceived through the frequency of a particular channel include the maindata, the enhanced data, and the table data which are used for decodingthe main data and enhanced data. In the example given in the presentinvention, traffic information data and a traffic information providingtable may be applied to the enhanced data.

The demodulator 702 performs VSB demodulation and channel equalizationprocesses on the signal outputted from the tuner 701. Then, afteridentifying the main data and the traffic information data from thesignal, the demodulator 702 outputs the data (or signal) by TS packetunits. The structure and operation of the demodulator 702 will bedescribed in detail in a later process. In the example of the presentinvention, only the traffic information data packet outputted from thedemodulator 702 is inputted to the demultiplexer 703. In other words,the main data packet may be inputted to another demultiplexer (notshown) that processes main data packets. Furthermore, the presentinvention may also be designed in a way that the demultiplexer 703 alsodemultiplexes the enhanced data packet as well as the main data packet.In the description of the present invention, the receiving andprocessing of traffic information data are described in detail. And, itshould be noted that a detailed description of the processing of maindata starting from the demultiplexer 703 may be omitted.

The demultiplexer 703 demultiplexes the traffic information messages andthe PSI/PSIP tables from the traffic information data packets beinginputted based upon the control of the data decoder 710. Thereafter, thedemultiplexed traffic information messages and PSI/PSIP tables areoutputted to the data decoder 710 in a section format. In an examplegiven in the present invention, a traffic information message carried bya payload within the TS packet is outputted in a DSM-CC section format.At this point, the demultiplexer 703 performs a section filteringprocess based upon the control of the data decoder 710 so as to deleteduplicate sections and to output only the non-duplicate sections to thedata decoder 710. Moreover, the demultiplexer 703 may output the sectionconfiguring a desired table (e.g., VCT) through a section filteringprocess to the data decoder 710. Herein, the VCT includes trafficinformation descriptors shown in FIG. 7. The traffic informationdescriptors may also be included in the PMT.

The section filtering method includes a method of initiating sectionfiltering after verifying the PID of a table defined by the MGT (e.g.,VCT), and, when the VCT has a fixed PID (i.e., a base PID), a method ofinitiating section filtering without verifying the MGT. At this point,the demultiplexer 703 performs section filtering by referring to thetable_id field, the version_number field, the section_number field, andso on. The data decoder 710 parses the DSM-CC section configuring thedemultiplexed traffic information message. Then, the data decoder 710decodes the traffic information message being a result of the parsingprocess and, then stores the traffic information message in a databaseof the second memory 711. The data decoder 710 groups a plurality ofsections having the same table identifiers (table_id) to configure andparse a table. Then, the data decoder 710 stores the system informationbeing the parsed result in the database of the second memory 711.

The second memory 711 is a table and data carousel database storingsystem information parsed from the tables and traffic informationmessages parsed from the DSM-CC section. Whether or not a table isconfigured of a single section or a plurality of sections can be knownby the table_id field, the section_number field, and thelast_section_number field within the table. For example, grouping onlythe TS packets having the PID of the VCT becomes a section. On the otherhand, grouping sections having table identifiers allocated to the VCTbecomes the VCT.

When parsing the VCT, information on the virtual channel to whichtraffic information is transmitted may be obtained. In addition,supplemental information associated with the traffic information messagedescribed, as shown in FIG. 7, in the traffic information descriptorsincluded in the VCT may also be obtained. More specifically, whenparsing the traffic information descriptors, application identificationinformation, service component identification information, serviceinformation (e.g., service name, service description, service logo,subscriber information, free text information, help information, etc.),and so on, of the traffic information message being transmitted to thecorresponding virtual channel can be obtained.

The application identification information, service componentidentification information, and service information of the trafficinformation message obtained as described above may either be stored inthe second memory 711 or outputted to the data broadcasting applicationmanager 713. Additionally, reference may be made to the applicationidentification information, service component identificationinformation, and service information for decoding the trafficinformation message. Alternatively, the application identificationinformation, service component identification information, and serviceinformation may also be used for preparing the operation of theapplication program for the traffic information message.

The data decoder 710 controls the demultiplexing of the systeminformation table corresponding to the table associated with channel andevent information. Thereafter, the data decoder 710 can transmit an A/VPID list to the channel manager 707. The channel manager 707 may referto the channel map 708 to send a request (or command) for receiving aninformation table associated with the system, and then the channelmanager 707 can receive the corresponding result. The channel manager707 may also control the channel tuning of the tuner 701. Furthermore,the channel manager 707 directly controls the demultiplexer 703 so as todirectly set up the A/V PID, thereby controlling the audio and videodecoders 704 and 705.

The audio and video decoders 704 and 705 may respectively decode andoutput the audio and video data demultiplexed from the main data packet,or respectively decode and output the audio and video data demultiplexedfrom the traffic information data packet. Meanwhile, according to theembodiment of the present invention, it is apparent that when trafficinformation data and also audio data and video data are included in theenhanced data, the audio data and video data demultiplexed by thedemultiplexer 703 may be respectively decoded by the audio decoder 704and the video decoder 705. For example, the audio decoder 704 may decodethe audio data by using an audio coding (AC)-3 decoding algorithm, andthe video decoder 705 may decode the video data by using an MPEG-2decoding algorithm.

Meanwhile, the native TV application manager 706 operates a nativeapplication program stored in the first memory 709, thereby performinggeneral functions such as channel switching. The native applicationprogram refers to a software that is being mounted upon shipping of thereceiving system. More specifically, when a user request is transmittedto the receiving system through a user interface (UI), the native TVapplication manager 706 the request onto the screen through a graphicuser interface (GUI), thereby responding to the user request. The userinterface receives the user request through an inputting device, such asa remote controller, a key pad, a jog dial, and a touch screen providedon the display screen. Thereafter, the user interface outputs thereceived user request to the native TV application manager 706, the databroadcasting application manager 713, and so on.

The native TV application manager 706 controls the channel manager 707,thereby controlling channel associated operations, such as managing thechannel map 708 and controlling the data decoder 710. In addition, thenative TV application manager 706 stores the GUI control, of the generalreceiving system, the user request, and the status of the receivingsystem to the first memory 709, and also recovers the information storedin the first memory 709. The channel manager 707 controls the tuner 701and the data decoder 710, thereby managing the channel map 708 so as tobe able to respond to the channel request made by the user.

More specifically, the channel manager 707 sends a request to the datadecoder 710 so that the table associated with the channel, which is tobe tuned, can be parsed. Thereafter, the channel manager 707 receives areport on the parsing result of the corresponding table from the datadecoder 710. Then, depending upon the reported parsing result, thechannel manager 707 updates the channel map 708. The channel manager 707also sets up a PID to the demultiplexer 703 so as to demultiplex thetable associated with the traffic information message from the trafficinformation data. The system manager 712 controls booting of thereceiving system by turning on and off the power and, then, stores a ROMimage (including downloaded software images) to the first memory 709. Inother words, the first memory 709 stores operation programs, such asoperation system (OS) programs required for operating the receivingsystem, and application programs performing data service functions.

The application program is a program that processes the trafficinformation message stored in the second memory 711, thereby providingthe traffic information service to the user. If a data broadcasting datatype other than the traffic information data is stored in the secondmemory 711, the corresponding data are processed by the applicationprogram or another type of application program and, then, provided tothe user. The operation program and application program stored in thefirst memory 709 may be updated or corrected with a newly downloadedprogram. Furthermore, since the stored operation program and applicationprogram are not deleted even when the driving power supply is shut down,when the driving power is supplied, the program can be performed withouthaving to download a new program.

The application program for providing the traffic information serviceaccording to the present invention may be mounted in the first memory709 upon shipping of the receiving system, or stored later on in thefirst memory 709 after being downloaded. Also, the application programfor the traffic information service (i.e., traffic information providingapplication program) that is stored in the first memory 709 can bedeleted, updated, and corrected. Furthermore, the traffic informationproviding application program may also be downloaded along with thetraffic information data and executed each time the traffic informationdata are being received.

When a data service request is made through the user interface, the databroadcasting application manager 713 operates the correspondingapplication program stored in the first memory 709 so as to process therequested data, thereby providing the requested data service to theuser. And, in order to provide such data service, the data broadcastingapplication manager 713 supports the GUI. Herein, the data service isprovided in the form of text, voice, graphic, still image, motionpicture, and so on. The data broadcasting application manager 713 may beprovided with a platform for executing the application program stored inthe first memory 709. The platform may be, for example, a Java virtualmachine for executing a Java program.

Hereinafter, an example of providing traffic information service to theuser by having the data broadcasting application manager 713 execute thetraffic information providing application program stored in the firstmemory 709 and, then, process the traffic information message stored inthe second memory 711 will now be described in detail. The trafficinformation service according to the present invention is provided tothe users by a receiver having only one or none of an electronic map anda GPS mounted therein in the form of at least one of a text, a voice, agraphic, a still image, and a motion picture. If the GPS module 714 ismounted on the receiving system shown in FIG. 17, the GPS module 714receives satellite signals transmitted from a plurality of low earthorbit satellites so as to extract a current location information (i.e.,longitude, latitude, altitude), thereby outputting the extractedinformation to the data broadcasting application manager 713. At thispoint, it is assumed that the electronic map including information oneach link and node and the various graphic information are stored in astorage unit (or memory) other than the first memory 709 or the secondmemory 711.

By executing the traffic information providing application program, thedata broadcasting application manager 713 provides the trafficinformation service requested by the user based upon the currentlocation information acquired from the GPS module 714 and the trafficinformation message stored in the second memory 711. More specifically,based upon the request of the data broadcasting application manager 713,the traffic information message stored in the second memory 711 is readand inputted to the data broadcasting application manager 713. The databroadcasting application manager 713 analyses the traffic informationmessage read from the second memory 711, thereby extracting requiredinformation and/or control signals in accordance with the contents ofthe message. In the description of the present invention, it is assumedthat a request for a CTT service has been made by the user.

More specifically, the data broadcasting application manager 713extracts date/time and message generation time included in the messagemanagement container of each TPEG message and determines if thefollowing container is a CTT status container based on ‘message element’information (i.e. an identifier). If it is determined that the followingcontainer is a CTT status container, the data broadcasting applicationmanager 713 provides the information extracted from the CTT componentincluded in the CTT status container. The data broadcasting applicationmanager 713 may display congestion and travel time status and predictedcongestion and travel time status, which will be described below. Theinformation extracted from the CTT component may include determining,based on identifiers, that the traffic information includes a messagemanagement container including status information within various messagecomponents within the message management container. The components mayeach include different status information associated with differentlinks or locations and identifiers associated with the different statusinformation. The containers and components may each include informationassociated with a generation time, version number, data length, andidentifiers of included information.

The data broadcasting application manager 713 then extracts informationon the link location for which the previously extracted information isintended from the following TPEG location container. The positioninformation may be, for example, the coordinates (i.e., latitudes andlongitudes) of the start and end positions or an ID that is uniquelyassigned to each link, depending on the type of the TPEG locationcontainer. If the terminal is equipped with the second memory 711, Thedata broadcasting application manager 713 finds the location of the linkfor which the received traffic information is intended with reference tothe information on each link and node stored in the second memory 711.The data broadcasting application manager 713 may convert thecoordinates of a link into a link ID or vice versa.

The data broadcasting application manager 713 reads a part of theelectronic map centered around the position coordinates received fromthe GPS module 714, and displays the read electronic map data on adisplay screen. In this case, a specific graphic sign is displayed at aspecific point corresponding to the current location.

The data broadcasting application manager 713 displays the average linkspeed at a location corresponding to the coordinates or link IDdelivered via the TPEG location container following the containerdelivering the average link speed. There are various processes for thedata broadcasting application manager 713 to display the trafficinformation.

For example, the data broadcasting application manager 713 may showlinks in different colors. For example, if the road on the image isdetermined to a current road, the red color is indicative of 0 to 10 kmper hour, the orange color is indicative of 10 to 20 km per hour, thegreen color is indicative of 20 to 40 km per hour, and the blue color isindicative of at least 40 km per hour. If the congestion changeinformation has a specific value, or a character string (“Increase” or“Reduction”) or icon assigned to the specific value “1” or “2” may alsobe displayed on a corresponding link along with the congestion changeinformation. If the congestion change information has a specific value“0” or “3”, a displayed status is not updated to a new status, such thata current displayed status remains. If the congestion accelerationtendency is received in the form of the rate of change of the averagespeed, the data broadcasting application manager 713 displays the valueonly when a request from the user is received to prevent visualconfusion of the user. The rate of change may be displayed together fora user-chosen route or a front link.

If the terminal does not include the second memory unit 711 equippedwith the electronic map, an average link speed associated with only aforward link of a current traveling path may be displayed in differentcolors, or may be displayed in different numerals. If the route of thevehicle with the terminal installed is determined, the terminal may showthe average speed at the links included in the determined route insteadof the links located in front of the current position.

The data broadcasting application manager 713, responsive to user input,may display the link travel time, the link delay, and the congestiontype instead of or simultaneously with the average link speed.

If the user requests predicted congestion and travel time status, thedata broadcasting application manager 713 displays the predicted averagelink speed at each link in colors or in numbers instead of the currentaverage link speed. In this case, the colors or numbers describing thepredicted status may be displayed simultaneously with the currentaverage link speed but the location or used colors may be different. Ifthe user switches the display mode to see the predicted link travel timeinstead of the predicted average link speed, the data broadcastingapplication manager 713 displays the predicted link travel time on theelectronic map or graphics on a display screen.

If the data broadcasting application manager 713 is capable of routing,the data broadcasting application manager 713 may search or research thedesirable route based on the received predicted average link speed orpredicted link travel time. For example, the data broadcastingapplication manager 713 finds the shortest time path to the destinationby using the predicted link average time or predicted link travel timeat each link to be reached 30 minutes later at the current speed.

If the terminal is equipped with a voice output capability, the terminalmay audibly output the received predicted status or congestion tendencyinformation for a specified link or links.

The information and/or control signals are temporarily stored in therewritable memory and used by the data broadcasting application manager713. After using the information stored in the memory, the databroadcasting application manager 713 may store the average link speed orlink travel time at intervals of, such as, for example, 20 minutes(e.g., 1:00, 1:20, 1:40) for the last 1 hour. The interval of storagemay differ depending on the storage capacity of the memory. Byautomatically expiring the information from within memory, the systemmay be assured that it is working with recent information whenconsulting the contents of the memory, and thus may be able to representinformation as current with confidence without having to otherwisemaintain or check information reflecting when the stored data wascollected/aggregated/stored.

If a specific link is selected by the user while the average speed ateach link is stored in the memory, the data broadcasting applicationmanager 713 controls a display screen so that the history of the averagelink speed or the history of the link travel time at the specified linkis displayed as a graph. The link name is received along with thecoordinates of the link or link ID through the TPEG location containeror included in the electronic map stored in the second memory 711. Thecurrent congestion status, predicted congestion status, or other statusmay be displayed in other or different ways.

If the predicted congestion status is not included in the receivedtraffic information, the data broadcasting application manager 713 maypredict the average speed using the current average speed and thehistory of the average link speed stored in the memory, and displays thepredicted average link speed. The method for predicting the average linkspeed may be the same as the aforementioned prediction method executedin the traffic information provider.

FIG. 18 illustrates a flow chart showing process steps of receiving andprocessing traffic information data according to an embodiment of thepresent invention. Referring to FIG. 18, a method of processing trafficinformation data according to the present invention will now bedescribed in detail. More specifically, when the power of the receivingsystem is turned on (S721), and when a channel selection or channelswitching is inputted (S722), a received channel signal is tuned to aphysical frequency so as to correspond to the selected or switchedchannel by using the channel map (S723). Herein, the channel selectionor channel switching is performed in accordance with a user command or asystem command.

At this point, the traffic information data having the trafficinformation message and the system information multiplexed therein maybe received through the channel frequency tuned as described above. Ifthe traffic information data are received (S724), the demultiplexer 703may demultiplex the traffic information message and system informationtables by using PID extraction and section filtering (S725). Among thesystem information, tables associated with channel information includethe VCT or the PAT/PMT. Herein, at least one of the PMT and VCT mayinclude the traffic information descriptor(s) according to the presentinvention. By parsing the system information table, information on thevirtual channel can be obtained, and whether an A/V element stream isbeing transmitted to the corresponding virtual channel and whether thetraffic information data are being transmitted can be known. If thetraffic information data are transmitted to the virtual channel, anapplication identifier, a service component identifier, and serviceinformation can be acquired by parsing the traffic informationdescriptor.

More specifically, information on the virtual channel is extracted byreferring to an element stream type (ES type) and PID within the systeminformation table (i.e., VCT and/or PAT/PMT) (S726). If the channelinformation extracted from the system information table indicates thatan A/V ES exists within the virtual channel (S727), an A/V PID of thecorresponding virtual channel in the channel map is set up (S728),thereby performing A/V demultiplexing and decoding (S729). Therefore,the user can view the broadcast program corresponding to the A/V (S730).Meanwhile, if it is indicated in Step 727 that an A/V ES does not existin the virtual channel, the present invention verifies when the trafficinformation data are being transmitted to the virtual channel (S731).

A plurality of methods for verifying whether the traffic informationdata have been transmitted to the virtual channel may be proposed. Forexample, verification can be performed by parsing the system informationtable, and verification can also be performed by using the PID withinthe TS packet. When assuming that the traffic information data have beentransmitted to the DSM-CC section, the existence (or presence) of thetraffic information data can be known by parsing the field value of anyone of the stream_type field within the PMT and the stream_type field ofthe service location descriptor within the VCT. In other words, if thestream_type field value is ‘0x95’, this indicates that the trafficinformation data have been transmitted to the corresponding virtualchannel. Therefore, if it is verified in Step 731 that the trafficinformation data are being transmitted to the virtual channel, alltraffic information having the DSM-CC data format that are beingtransmitted to the virtual channel are received (S732), therebyproviding the traffic information service desired (or requested) by theuser (S733).

If it is verified, in Step 731, that neither the A/V ES nor the trafficinformation data exist in the virtual channel, then the correspondingvirtual channel is determined to be an invalid channel. In this case,the system may display, for example, a message that no valid channel orsignal exists (S736). Thereafter, the process is returned to Step 724 inorder to newly receive a valid channel information table.

Meanwhile, the system verifies whether a request for changing (orswitching) the channel is made during the data service or while viewinga broadcast program (S734). If a change in channel has been requested,and if the request corresponds to changing the virtual channel, the databroadcasting process is reset, and the process is returned to Step 726in order to find a new set of virtual channel information. Further, ifthe request corresponds to changing the physical channel, the process isreturned to Step 723 so as to tune to the corresponding physicalchannel.

However, if there is no request for changing the channel, the systemverifies whether a channel information version has been upgraded (S735).If it is determined in Step 735 that the channel information version hasbeen upgraded, this indicates that the channel information has beenchanged (or modified) by the broadcast station. Therefore, the processis returned to Step 724 in order to receive a new channel informationtable. Conversely, if it is determined in Step 735 that the channelinformation has not been changed (or modified), then viewing of thebroadcast program may be resumed.

The demodulator (reference numeral 702 of FIG. 17) according to thepresent invention uses the known data information that is inputted to atraffic information data section and, then, transmitted by atransmitting system so as to perform process such as carrier wavesynchronization recovery, frame synchronization recovery, channelequalization, and so on. Thus, the receiving performance can beenhanced. FIG. 19 and FIG. 20 respectively illustrate detailed blockviews of the demodulator shown in FIG. 17.

Referring to FIG. 19, the demodulator includes a VSB demodulator 761, anequalizer 762, a known sequence (or data) detector 763, an E-VSB blockdecoder 764, an E-VSB data processor 765, and a main data processor 766.More specifically, an intermediate frequency (IF) signal of a channelfrequency tuned by the tuner 701 (shown in FIG. 17) is inputted to theVSB demodulator 761 and the known sequence detector 763. The VSBdemodulator 761 performs self gain control, carrier wave recovery, andtiming recovery processes on the inputted IF signal, thereby modifyingthe IF signal to a baseband signal. Then, the VSB demodulator 761outputs the newly created baseband signal to the equalizer 762 and theknown sequence detector 763. The equalizer 762 compensates thedistortion of the channel included in the demodulated signal and thenoutputs the error-compensated signal to the E-VSB block decoder 764.

At this point, the known sequence detector 763 detects the knownsequence location inserted by the transmitting end from the input/outputdata of the VSB demodulator 761 (i.e., the data prior to thedemodulation or the data after the modulation). Thereafter, the locationinformation along with the symbol sequence of the known data, which aregenerated from the detected location, is outputted to the VSBdemodulator 761 and the equalizer 762. Further, the known sequencedetector 763 outputs information related to the traffic information dataadditionally coded by the transmitting end and the main data that havenot been additionally coded to the E-VSB block decoder 764. Herein, theinformation allowing the traffic information data and the main data tobe differentiated (or identified) by the E-VSB block decoder 764 isoutputted to the E-VSB block decoder 764. Although the connection stateis not shown in FIG. 19, the information detected by the known sequencedetector 763 may be used throughout almost the entire receiving system.Herein, the detected information may also be used in the E-VSB datadeformatter 765-1 and in the RS frame decoder 765-2.

The VSB demodulator 761 uses the known data symbol sequence during thetiming and/or carrier recovery, thereby enhancing the demodulatingperformance. Similarly, the equalizer 762 uses the known data sequence,thereby enhancing the equalizing performance. Furthermore, the decodingresult of the E-VSB block decoder 764 may also be fed-back to theequalizer 762, thereby enhancing the equalizing performance. Meanwhile,when the data being inputted to the E-VSB block decoder 764, after beingequalized by the equalizer 762, correspond to the traffic informationdata being additionally coded and trellis-encoded by the transmittingend, the equalizer 762 performs an inverse process of the transmittingend by additionally decoding and trellis-decoding the inputted enhanceddata. On the other hand, when the data being inputted correspond to themain data being trellis-encoded only and not additionally coded, theequalizer 762 only performs trellis-decoding on the inputted main data.

The data group decoded by the E-VSB block decoder 764 is outputted tothe E-VSB data processor 765, and the main data packet is outputted tothe main data processor 766. More specifically, when the inputted datacorrespond to the main data, the E-VSB block decoder 764 performsViterbi-decoding on the input data so as to output a hard decision valueor to perform hard decision on a soft decision value and output thehard-decided result. Meanwhile, when the inputted data correspond to thetraffic information data, the E-VSB decoder 764 outputs a hard decisionvalue or a soft decision value on the inputted enhanced value.

More specifically, when the inputted data correspond to the trafficinformation data, the E-VSB block decoder 764 performs a decodingprocess on the data encoded by the E-VSB block processor and the trellisencoder of the transmitting system. At this point, the data outputtedfrom the RS frame encoder of the E-VSB pre-processor included in thetransmitting system may correspond to an external code, and the dataoutputted from each of the E-VSB block processor and the trellis encodermay correspond to an internal, code. When decoding such concatenatedcodes, the decoder of the internal code should output a soft decisionvalue, so that the external coding performance can be enhanced.Therefore, the E-VSB block decoder 764 may output a hard decision valueon the traffic information data. However, it is more advantageous tooutput a soft decision value.

As an example of the present invention, the E-VSB data processor 765includes an E-VSB data deformatter 765-1, a RS frame decoder 765-2, andan E-VSB derandomizer 765-3. It would be efficient to apply thisstructure in the E-VSB pre-processor of the transmitting system (shownin FIG. 11) which includes an E-VSBG randomizer, a RS frame encoder, anE-VSB block processor, a group formatter, a data deinterleaver, and apacket formatter. The main data processor 766 includes a datadeinterleaver 766-1, a RS decoder 766-2, and a data derandomizer 766-3.

Herein, the data deinterleaver 766-1, the RS decoder 766-2, and the dataderandomizer 766-3 included in the main data processor 766 are blocksrequired for receiving the main data. Therefore, these blocks may not berequired in the structure of the receiving system that only receives thetraffic information data. The data deinterleaver 766-1 performs aninverse process of the data interleaver included in the transmittingend. More specifically, the data deinterleaver 766-1 deinterleaves themain data being outputted from the E-VSB block decoder 764 and outputsthe deinterleaved data to the RS decoder 766-2.

The RS decoder 766-2 performs systematic RS decoding on thedeinterleaved data and outputs the RS-decoded data to the dataderandomizer 766-3. The data derandomizer 766-3 receives the output ofthe RS decoder 766-2 and generates a pseudo random data byte identicalto that of the randomizer included in the transmitting system.Thereafter, the data derandomizer 766-3 performs a bitwise exclusive OR(XOR) operation on the generated pseudo random data byte, therebyinserting the MPEG synchronization bytes to the beginning of each packetso as to output the data in 188-byte main data packet units. At thispoint, the output of the data derandomizer 766-3 may be inputted to thedemultiplexer 703 shown in FIG. 17. Alternatively, the output of thedata derandomizer 766-3 may be inputted to a main data specificdemultiplexer (not shown), which demultiplexes the A/V data and channelinformation associated tables from the main data.

The data being outputted from the E-VSB block decoder 764 are inputtedto the E-VSB data deformatter 765-1 in a data group form. At this point,the E-VSB data deformatter 765-1 already knows the configuration of theinput data group. Accordingly, the E-VSB data deformatter 765-1 removesthe main data, the known data that have been inserted in the data group,the trellis initialization data, the MPEG header, and the RS parityadded by the RS encoder of the transmitting system that all wereinserted in the main data group. Thereafter, the E-VSB data deformatter765-1 outputs only the traffic information data to the RS frame decoder765-2. More specifically, the RS frame decoder 765-2 receives only thetraffic information data RS-coded and/or CRC-coded by the E-VSB datadeformatter 765-1.

The RS frame decoder 765-2 performs an inverse process of the RS frameencoder included in the transmitting system. Accordingly, the RS framedecoder 765-2 corrects the errors within the RS frame. Thereafter, theRS frame decoder 765-2 adds a 1-byte MPEG synchronization byte, whichwas removed during a RS frame coding process, to the error-correctedtraffic information data packet. Then, the processed data are outputtedto the E-VSB data derandomizer 766-3. At this point, if a rowpermutation process was performed on the traffic information data, aninverse row permutation process is also required. The E-VSB dataderandomizer 766-3 performs a derandomizing process, which correspondsto an inverse process of the E-VSB randomizer included in thetransmitting system, on the inputted traffic information data andoutputs the processed data. Thus, the transmitting system can receivethe transmitted traffic information data.

Meanwhile, if the E-VSB randomizer is positioned after the RS frameencoder in the structure of the E-VSB pre-processor included in thetransmitting system, the E-VSB data processor may include only the E-VSBdata deformatter and the RS frame decoder. In this case, the operationof the E-VSB data deformatter becomes partially different from that ofthe E-VSB data deformatter shown in FIG. 19. In other words, thedifference between the E-VSB data deformatter of FIG. 19 and theabove-described E-VSB data deformatter is that a derandomizing processis first performed on the traffic information data, and the RS framedecoding process is performed afterwards.

In this case, only the data derandomizing process may be performed, orthe data derandomizing process may be processed along with the null dataremoving process. This may differ depending upon the structure andoperation of the E-VSB pre-processor included in the transmittingsystem. More specifically, only the data derandomizing process may beperformed, or the data derandomizing process and the null data removingprocess may both be processed depending upon the positioning order ofthe E-VSB block processor and the group formatter, and whether thecoding process was performed only on the valid data by the E-VSB blockprocessor.

For example, if the E-VSB block processor is positioned before the groupformatter in the E-VSB pre-processor, the receiving system does notrequire the null data to be removed, since byte expansion has not beenperformed. In addition, even though a byte expansion process has beenperformed, if the E-VSB block processor has performed an additionalcoding process only on the valid data (e.g., if the coding process wasperformed at a coding rate of 1/2 or at a coding rate of 1/4), thereceiving system does not require the process of removing the null data.Conversely, if the E-VSB block processor is positioned after the groupformatter in the E-VSB pre-processor, the receiving system requires abyte expansion process to be performed this case, if the E-VSB blockprocessor has performed an additional coding process all data types(e.g., if the coding process was performed at a coding rate of 1/2 or ata coding rate of 1/4), the receiving system requires the null data to beremoved.

However, if the removal of the expanded byte is required, the order ofthe byte removal process and the derandomizing process may varydepending upon the structure of the transmitting system. Morespecifically, if the byte expansion is performed after the randomizingprocess in the transmitting system, then the byte removal process isfirst performed before performing the derandomizing process in thereceiving system. Conversely, if the order of the process is changed inthe transmitting system, the order of the respective processes in thereceiving system is also changed.

When performing the derandomizing process, if the RS frame decoderrequires a soft decision in a later process, and if, therefore, theE-VSB block decoder receives a soft decision value it is difficult toperform an XOR operation between the soft decision and the pseudo randombit, which is used for the derandomizing process. Accordingly, when anXOR operation is performed between the pseudo random bit and the softdecision value of the traffic information data bit, and when the pseudorandom bit is equal to ‘1’, the E-VSB data deformatter changes the codeof the soft decision value and then outputs the changed code. On theother hand, if the pseudo random bit is equal to ‘0’, the E-VSB datadeformatter outputs the soft decision value without any change in thecode. Thus, the state of the soft decision may be maintained andtransmitted to the RS frame decoder.

If the pseudo random bit is equal to as described above, the code of thesoft decision value is changed because, when an XOR operation isperformed between the pseudo random bit and the input data in therandomizer of the transmitter, and when the pseudo random bit is equalto ‘1’, the code of the output data bit becomes the opposite of theinput data (i.e., 0 XOR 1=1 and 1 XOR 0=0). More specifically, if thepseudo random bit generated from the E-VSB packet deformatter is equalto ‘1’, and when an XOR operation is performed on the hard decisionvalue of the traffic information data bit, the XOR-operated valuebecomes the opposite value of the hard decision value. Therefore, whenthe soft decision value is outputted, a code opposite to that of thesoft decision value is outputted.

Accordingly, the RS frame decoder performs an inverse process of the RSframe encoder included in the transmitting system. Therefore, the RSframe decoder corrects the errors within the RS frame. Subsequently, theRS frame decoder adds a 1-byte MPEG synchronization byte, which wasremoved during a RS frame coding process, to the error-corrected trafficinformation data packet. Thus, the initial traffic information datatransmitted by the transmitting system can be obtained.

FIG. 20 illustrates a detailed block view of the demodulator accordingto a second embodiment of the present invention. Referring to FIG. 20,the demodulator includes a VSB demodulator 781, an equalizer 782, aknown sequence (or data) detector 783, a Viterbi decoder 784, a datadeinterleaver 785, a RS decoder 786, a data derandomizer 787, and anE-VSB data processor 788. Herein, the E-VSB data processor 788 includesa main data packet remover 788-1, an E-VSB packet deformatter 788-2, andan E-VSB data processor 788-3. It would be efficient to apply thedemodulator shown in FIG. 20 to the transmitting system having thestructure shown in FIG. 16. Furthermore, the VSB demodulator 781, theequalizer 782, and the known sequence detector 783 are identical tothose shown in FIG. 19. Therefore, since reference can be made for thestructure of the same components, a detailed description of the samewill be omitted for simplicity.

The Viterbi decoder 784 Viterbi-decodes the data outputted from theequalizer 782 and converts the Viterbi-decoded data to bytes.Thereafter, the converted data are outputted to the data deinterleaver785. The data deinterleaver 785 performs an inverse process of the datainterleaver of the transmitting system and outputs the deinterleaveddata to the RS decoder 786. If the received data packet is the main datapacket, the RS decoder 786 RS-decodes the received main data packet.Alternatively, if the received data packet is the traffic informationdata packet, the RS decoder 786 removes the non-systematic RS paritybytes and outputs the processed data to the data derandomizer 787.

The data derandomizer 787 performs an inverse process of the randomizerof the transmitting system on the output of the RS decoder 786.Thereafter, the data derandomizer 787 inserts the MPEG synchronizationbyte in the beginning of each packet, thereby outputting the data in188-byte packet units. The output of the data derandomizer 787 issimultaneously outputted to the demultiplexer 703 (shown in FIG. 17) orthe main data specific demultiplexer (not shown) and outputted to themain data packet remover 788-1 of the E-VSB data processor 788.

The main data packet remover 788-1 removes the 188-byte main data packetfrom the data outputted from the data derandomizer 787 and outputs theprocessed data to the E-VSB packet deformatter 788-2. The E-VSB packetdeformatter 788-2 removes the 4-byte MPEG header, known data, andtrellis initialization data from the 188-byte data packet. Then, theE-VSB packet deformatter 788-2 outputs only the traffic information datato the E-VSB data processor 788-3. At this point, the E-VSB packetdeformatter 788-2 may or may not remove the null data.

More specifically, when the E-VSB post-processor of the transmittingsystem shown in FIG. 16 performs additional coding on the trafficinformation data, and, accordingly, when the coding is performed only onthe valid traffic information data, the removing of the null data is notrequired. Conversely, however, if the additional coding process isperformed on all byte-expanded traffic information data, the null datamust be removed. The E-VSB data processor 788-3 performs an inverseprocess of the E-VSB pre-processor included in the transmitting systemon the output of the E-VSB packet deformatter 788-2. Thus, the trafficinformation data initially transmitted from the transmitting system maybe obtained.

As described above, the digital broadcast transmitting/receiving systemand the method for processing data are advantageous in that whenreceiving traffic information data through a channel, the data arerobust against error and are compatible with the conventional VSBreceiver. Furthermore, data can be received more efficiently withouterror even in channels having severe noise and ghost effect.

In addition, by performing additional error correction coding and errordetection coding processes on the traffic information data andtransmitting the processed data, robustness is provided to the trafficinformation data, thereby allowing the data to respond appropriately tothe changes in the channel environment. Furthermore, by using linkidentifiers for providing the traffic information data, the transmissioncapacity may be minimized. And, by warning in advance the information onheavy congested traffic status, the amount of traffic may be adequatelydispersed, thereby allowing the roads to be circulated efficiently. Thepresent invention having the above-described advantages may be moreefficiently used when applied in mobile and portable receiver whichrequires a greater degree of robustness against noise and ghost effect.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the present inventionwithout departing from the spirit or scope of the inventions. Thus, itis intended that the present invention covers the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

1. A digital broadcast transmitter, comprising: a pre-processorconfigured to pre-process enhanced data and known data; a multiplexerconfigured to multiplex the enhanced data with one or more main audioand video data; a trellis encoder configured to have at least one memoryand trellis-encode the multiplexed data, the at least one memory beinginitialized by initialization data when input data corresponds to abeginning of a sequence of the known data; and a data transmission unitconfigured to insert synchronization data into the trellis-encoded data,modulate the trellis-encoded data having the synchronization data, andtransmit the modulated data, wherein the pre-processor comprises: a RSframe encoder configured to encode each RS frame for at least one of anerror correction and an error detection; a block encoder configured toencode the enhanced data encoded by the RS frame encoder with a codingrate of G/H, wherein G and H are positive integers and G is less than H;a group formatter configured to insert the enhanced data encoded by theblock encoder and the known data into a data group having a plurality ofregions, the data group including a first, a second and a third region,the second region being positioned between the first and third regions,the first and third regions including the enhanced data, placeholdersfor main data and RS parity bytes, and the second region including theenhanced data and placeholders for MPEG header bytes and RS paritybytes; a data deinterleaver configured to deinterleave data included inthe data group; and a packet formatter configured to add header data tothe deinterleaved data to generate data packets.
 2. The digitalbroadcast transmitter of claim 1, further comprising: an encoderconfigured to add first parity data to the multiplexed data; and a datainterleaver configured to interleave the multiplexed data having thefirst parity data.
 3. The digital broadcast transmitter of claim 2,further comprising: a compatible processor configured to calculatesecond parity data from the interleaved data and the initializationdata, and replace the first parity data within the interleaved data withthe second parity data.
 4. The digital broadcast transmitter of claim 1,wherein the group formatter further inserts header location holders,main AV data holders, and parity data location holders into the datagroup.